The definition of “le” in the part-of-speech system of Huang and Liao’s “Modern Chinese” (Sixth Edition) is:

1) Aspectual particle. Used after verbs and adjectives, it means the realization of actions or behaviors has become a fact. “This feature is usually called “le₁”.

2) Modal particles. The function of modal particles is to express the mood, which is mainly used at the end of a sentence, and can also be used in a sentence where there is a pause after the subject and the adverbial. The tone of “le” means declarative tone, imperative tone, “represents the emergence of new situations” and “help complete a sentence”. This feature is usually called “le₂”.

3) When used continuously at the end of the sentence, such as “自行车他骑走了”, “枫树的叶子红了”. The “le” at the end of this sentence not only indicates the realization of the behavior, but also the change of the state of affairs. Some people categorize this use as “le₃”.

The above points can be said to be the basic consensus in the relevant academic field. However, apart from these common distinctions, there are also some different points of view.

Discussions on the “le₁” focus on the following: Firstly, does it really show the “realization” or “completion” aspect? Secondly, what are the conditions of its use? That is, under which circumstances should it be used, when can it be used and when should it not be used? Thirdly, what is the relationship between it and the concept of “tense”? We will discuss these questions below.

Regarding the first question, that is, whether it really means the “realization” or “completion” of actions, native English speakers have a perfect aspect in their mother tongue. They can easily associate the concept of “completion” with reference to their own language. In fact, there are some actions in Chinese that have not been completed even though “le” has been added. Liu (1988) does not agree with the “completion” theory, but believes that “le₁” is a marker of “realization”, indicating that the meanings of verbs, adjectives and other predicate forms are in a state of fact. Although in sentences like “说了就放心了” “吃了就走”, “le” actually means completion, “le” in the two examples of “低了头”and “红了脸” can be replaced by “zhe” without changing the meaning: “低着头” and “红着脸”. The point is that the “低” and “红” actions are not over, but they are in progress. Other examples such as “疯了许多年”, “终于过上了好日子”, “打了起来”, etc. are also the same. Based on this, Jin (2002) started from the semantic types of verbs, and further proved the three situations of the corresponding action states: “吃” (weakly action-continuous verbs) plus “le” and the behavior was implemented. When “le” comes after strong action-continuous verbs, such as “了解”, the behavior is implemented and continues and in non action-continuous verbs or adjective, such as “死” and “红” the use of “le” indicates that the behavior has been achieved and the changed state continues to hold. In addition, the article also examines the situation of “V + le + O” with a time period attributive and a subject. It is proved that the particle “le₁” works with other syntactic conditions to give the verbs “end continuation”, “behavior continuation” and “state continuation”. In summary, “realization” includes “completion”. Regardless of whether the action ends or the stage the action has reached, the premise is that it has been “realized”, otherwise there is no way to talk about it. So obviously “realization” is a more general term. Wang & Huang (2020) believe that “le₁” shows that the whole or a phase of the internal process of the action or state has reached the end. In fact, it is consistent with the term “realization”.

Regarding the second point, concerning the conditions of its use, Fan (2020) examined in detail the “le₁” distribution conditions, suggesting that its use is influenced by at least five grammar factors: the reality of the situation predicate, the predicate syntactic status, the situation of the sentence particles, the types of objects and the types of verbs. In this regard, it is believed that “le₁” is a tense marker that marks the time of an event and its use will naturally be subject to the temporal attribute of the predicate―that is, the reality (Fan, 2020: 192).

Regarding the third point, the relation of “le” with “tense”, Lin (2017) believes that “le” is not a mere aspect marker, but a marker that combines past tense and aspect meaning. The “time” here refers to the meaning of “relative past tense”. In fact, this could correspond to the English future perfect tense (will have done something). For example, “明天这个时候,她应该早就抵达了洛杉矶” The absolute time that time occurred is “明天这个时候”, but the action of “抵达” occurred before that. The author believes that although Chinese still doesn’t have a truly grammatically mature tense system, perhaps the aspectual marker will evolve into a tense marker in the future, “le” being a good example of this prospective process.

The discussion of “le₂” in academia is mainly focused on: 1) How to understand the three prevailing interpretations, i.e. “changes or new situations appear”, “confirmation tone, which means that things are done or realized” and “the function of forming sentences?” 2) “What are its subjective interactivity usages? 3) What is the law of co-occurrence with “le₁”? 4. What is its relation with “tense” and “aspect”? We will discuss these separately below.

Based on the previous studies above, we accept the premise that “le₁” is an aspectual particle indicating the realization of an action, carrying a relative past tense meaning, while its use is subject to various conditions, including the nature of the predicate, the complement and the appearance of “le₂”. “le₂” is a modal particle which indicates the realization of the state of affairs, it can indicate the appearance of changes or new situations, it has pragmatic functions such as “Please listen to me”, it indicates the relative past tense, it has strong subjective close interactivity, it is mostly used in speaking and it is seldom used in news reports and other scenarios.

Based on the characteristics of the teaching of grammar within the context of TCSOL, the theoretical basis of this article is that “le” is a particle, which means the realization of an action or state. It is used after the verb in the sentence and at the end of the sentence. When “le” is used at the end of the sentence, the meaning of “change” can be derived from the meaning of “realization”, as there are rich pragmatic functions such as “reminder” and “commitment” in communication, indicating a relative past time. In our approach, we merged the two traditional “le” uses into one, which can be further sub-categorized according to

syntactic, semantic and pragmatic functions. This can be shown in Figure 1 above. This article does not follow the traditional expression of “representing the affirmative tone of the realization or completion of the action”, because this is not very practical in the context of TCSOL.

As Table 1 below shows, after compiling the above grammatical points of the afore-mentioned textbooks, we believe that it is more appropriate to use “particle” to refer to “le₁” and “le₂”, as they are neither “auxiliary verbs” nor “dynamic auxiliaries”, but grammatical marker with rich grammatical functions. For “le₂”, the reason why we do not recommend using “modal particle” is that within the context of TCSOL such linguistic terms can be expected to further obscure grammatical points being taught.

As shown in Table 2 below, this book covers three main uses of “le”. However, it is not accurate to say that “le₂” only refers to the past, because it can actually express the future, such as in “明天晚上八点我就下飞机了”. Although the absolute time here is “tomorrow”, there is reference to a relative past tense. When the time reference is “tomorrow eight o’clock”, it is meant that the “getting off the plane” will have been completed before this point of time. Therefore, it refers to a realization of an action.

In addition, in this book, it is shown that “le” is used at the end of a sentence to have both functions of “le₁” and “le₂”. We believe that this does not enhance comprehension in teaching, so it is difficult for students to truly understand its meaning and we do not recommend introducing this statement to them. Comparing the sentences “他去了” and “我买衣服了”, the author of the textbook, in

the first example, meant that “去” is a bare verb and the original sentence “should” be “他去了₁了₂”. In the second example, with the verb “买” carrying an object, the original sentence can be “我买(了₁)衣服了₂”. However, we believe that we could, more efficiently, explain the two sentences in one paradigm. The use of “le” in these two sentences means that the behavior has been realized. In this manner, there is no need to add unnecessary and obscure information that does not facilitate the students’ understanding. If we really use the proposed “le₁ + le₂ = le₃”, then in fact many “le₂” sentences can be included in this category, as, according to the previous review, we know in sentences with co-occurring “le” particles, the reason why most “le₁” can often be omitted is because “le₂” provides “tense” or “tone”. For example, “我去(了₁)商场了₂”. This is an indication that traditional grammatical approaches need to be adapted in order to become effective within a pedagogical context.

According to the textbook, “le₂” is used after noun phrases and subject-predicate phrases to indicate change and to remind or attract others’ attention. We believe that the introduction of this usage is very good, suitable for the needs of communication. It includes the semantic level, indicating the change of the situation, and the pragmatic function level, which refers to drawing the listener’s attention. We believe that the sentence could be somewhat refined and introduce more detailed pragmatic functions, such as “reminder”, “commitment”, “recommendation” and so on. For examples, “吃饭了” (reminder), “别去了” (recommendation) “再见了” (promise), etc. These usages are not covered by traditional explanations and they do not indicate changes. We should distinguish this usage from those of “realization” or “change” of actions or states.

As Table 3 below shows, we believe that this set of textbooks is well-arranged in terms of the explanation of “le”, which is more consistent with our approach. Its purpose is to compile the two “le₁” and “le₂” into one “le”. This is probably a more effective approach. It should be noted that there are two different examples in Book 1 Lesson 5: “她今年50岁了” and “她女儿今年20岁”. Since both mean “change”, why does one carry “le” and the other doesn’t? In view of such a question that students may ask, the teacher needs to have a way to explain. According to the existing research, the “le” in the first sentence puts age in an axis, while the second sentence is just a simple and static statement of the fact. There is no significant difference between them. In Book 3, Lesson 5, it is mentioned that le “indicates the emergence of a new situation”, with all the example sentences being in the present tense. We think it would be better to also explain to students the past and future situations of “le”. For example: “我明年就不住在这儿了”. In fact, the similar sentence “我明天不能和你们出去玩了” has already appeared in the text. The important thing is that there are many pragmatic uses in this textbook, which are presented to students in detail in different formats, such as” 都……了” “要……了” “别提多……了”. We believe that this is very useful, communicative approach that reinforces students’ understanding.

Regarding the textbook shown in Table 4 that follows, we have pointed out the problem of terminology. In addition, in this book we can notice some inconsistency between the example sentences and the interpretation of the grammar

points. For example, in Lesson 13 of Book 2 it is said that “le₁” is used at the end of a word to indicate the realization or completion of an action, but the example sentence given is “我吃早饭了”, which is clearly the usage of “le₂”. The sentences in the text such as “早饭你吃了什么？” “我喝了一杯牛奶” “吃了两个鸡蛋” “我喝了一碗粥”, etc. are obviously typical “le₁” usage.

This set of textbooks does not list the usage of “le₂” to indicate the realization of the action, but only the usage to indicate the new situation, which we think is not adequate. Used at the end of the sentence, the basic function of “le₂” is to express the realization of an action or state, which is the same as “le₁”. The expression of the emergence of a new situation is an extended usage. According to the “principle of cooperation” of communication, an effective conversation must provide new information. For students, the explanation of the language points in the book cannot solve the language phenomenon encountered. For example, “你买什么了?” This does not mean the emergence of a new situation. Especially when students encounter two “did” co-occurrences, they will be even more confused, such as “你买了什么了？”.

In addition, there is the problem of incoherent interpretation of language points. For example, “别忘了拿作料来” in Lesson 13 of Book 3 and “等到严重就晚了！” in Lesson 14. Students cannot understand these two sentences based on their existing knowledge. In fact, one of these two example sentences can be explained by the subjective interactivity function of “le₂”, and the other is a typical usage of “le₂”. The sentence “别忘了拿作料来” can be converted to “拿作料来，别忘了！” In this case, “别忘了” is a parenthesis, which represents the pragmatic function of “to remind”. Students can understand this sentence by learning this phrase individually. The “le₂” in the sentence “等到严重就晚了” indicates the realization of the behavior.

The grammar point “adverb ke indicates emphasis” in Lesson 18 of Book 3, in

fact, “ke” here serves as an adverbial, which can be replaced with “相当” or “太” without changing the meaning. After studying this item, students still don’t know what the “le” in these sentences means and why they should use it. Our suggestion is the same as previously, that is, to add more pragmatic functions to the textbook.

As Table 5 below shows, this set of textbooks is also relatively complete in the arrangement of grammar points, covering the common usage of “le”. However, according to our definition, the distinction between “le₁” and “le₂” in the book is also unnecessary, especially for the interpretation of the term “express affirmative tone”, which is usually hard to understand by students. We recommend merging them. One thing worth noting is that this textbook proposes some

discourse and pragmatic uses of “le”, such as “别提了”, “对了”, etc. which are very suitable for the communication needs of Chinese learners.

To sum up the previous analysis of the four textbooks analysed in this paper, we recommend merging the traditional “le₁” and “le₂” in TCSOL, to include “realization of an action or state” covering different syntactic positions, as the concept of “realization” itself contains many states such as the occurrence, completion and continuation of actions. The use of “le₂”, meaning “affirmative tone”, and the “le₁ + le₂ = le₃” can be avoided. We suggest adding different pragmatic functions of “le” at the end of the sentence and emphasizing the difference between using “le” and not using “le” in the example sentences. Moreover, it is useful to explain the hidden laws of “le” from the perspectives of writing types, lexical reasons and writing style.

As Table 6 shows, At an elementary stage of introducing “le” to students, like with all other grammatical phenomena, we move from the shallower to the deeper, from simple to more complex uses. We can teach the fixed sentence pattern

with “le” first, then teach the “le₁” uses, and then teach the “le₂” uses.

At an intermediate stage, this function of “le” can be introduced and presented gradually at different points in different lessons. They are not annotated as a special grammar point, but only appear in the text with their interpretation. Examples are shown in Table 7 below.

As the awareness of students of more grammatical phenomena rises, more uses of le as a necessary particle can be introduced. In Table 8 that follows, we can see two such examples.

One last suggestion in the teaching of “le” is to take advantage of students’ wrong productions or instances where “le” cannot appear as shown in Table 9 below, in order to discuss its exclusion, in different lessons. In this way, students will gradually acquire a better understanding of where “le” must be avoided.