Four uses of verb tenses

1) since + a point in time in the past (such as a specific year, month, date, hour, 1980, last month, half past six).

I have been here since 1989

2) since + some time + ago

I have been here since five months ago

3) since + clause

Great changes have taken place since you left

Considerable time has elapsed since we have been here

4) It is + a period of time + since clause

It is two years since I became a postgraduate student.

Continuation verbs and momentary verbs

1) Differences in perfect tense

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Continuation verbs express experience and experience; momentary verbs express the results of actions and cannot be used with time adverbials expressing segments.

He has completed the work. (Table results)

I've known him since then. I've known him since then. (Experience)

2) Differences in till/until clauses

Continuation verbs are used in affirmative sentences to express... until... Momentary verbs are used in negative sentences to express Until..., just...

He didn't come back until ten o'clock.

He didn't come back until ten o'clock.

He didn't come back until ten o'clock.

He slept till ten o'clock.

He slept till ten o'clock.

Typical examples

1. You don't need to describe her. I ___ her several times.

A. had met B. have met C. met D. meet

Answer B. First, the last sentence of this question Emphasis on the impact on the present, I know what she looks like, you don’t need to describe it. Thirdly, several times tells a recurring action, so the present perfect tense is used.

2． ---I'm sorry to keep you waiting.

---Oh, not at all. I ___ here only a few minutes.

A. have been　B. had been　C. was　D. will be

Answer A. The action of waiting starts in the past and continues to the present, and the present perfect tense is applied. 1) Concept: expressing the past of the past

----|-------|-----|---->Its composition is had + past participle.

Before then, then, now

2) Usage

a. The object clause after verbs such as told, said, knee, heard, thought, etc.

She said (that) she had ever been to Paris.

She said (that) she had ever been to Paris.

b. Adverbial clause

Among two actions that happened at different times in the past, if it happened first, use the past perfect tense; if it happened later, use the past simple tense.

When the police arrived, the thieves had run away.

When the police arrived, the thieves had run away.

c. Verbs expressing intention, such as hope, wish, expect, think, intend, mean, suppose, etc., use the past perfect tense to express originally..., failed to...

We had hoped that you would come, but you didn't.

We hoped you could come then, but you didn’t

3) Past perfect time adverbial before, by, until, when, after, once, as soon as.

He said that he had learned some English before.

He said that he had learned some English before.

By the time he was twelve, Edison had began to make a living by himself.

When he was twelve years old, Edison began to make a living for himself

Tom was disappointed that most of the guests had left when he arrived at the party .

Tom was disappointed, most of the guests left the party when he arrived

Typical example

The students ___ busily when Miss Brown went to get a book she ___ in the office.

A. had written,left　B, were writing,has left　C. had written,had left　D. were writing,had left

Answer D. put Forgetting the book in the office happened before the past action of going to get the book, so the action of forgetting the book happened in the past past, using the past perfect tense. The word "when" in the sentence represents a point in time, indicating that the action guided by "when" occurs under the background that the students are busy... Therefore

The previous sentence should use the past continuous tense.

Note: Had no… when Before… just…

had no sooner… than just… Just…

He had no sooner bought the car than he sold it.

Simple past tense instead of perfect tense

1) If two actions occur in order and the order is not emphasized, then, and, but When using conjunctions, use the past tense.

When she saw the mouse, she screamed.

When she saw the mouse, she screamed

My aunt gave me a hat and I lost it.

My aunt gave me a hat, but I lost it

2) When two actions occur one after another, the past tense can be used; if the first action requires several Time is perfect, use the past perfect tense.

When I heard the news, I was very excited.

When I heard the news, I was very excited

3) It is not necessary to describe historical facts. Past perfect tense, and only past simple tense.

Our teacher told us that Columbus discovered America in 1492.

Our teacher told us that Columbus discovered America in 1492 1) Formation will / be going to do sth.

2) Concept

a. State completion: It means that something will continue until a certain time in the future.

b. Action completion: Indicates an action that has been completed or an experience gained at some time in the future or before another future action.

They will have been married for 20 years by then.

They have been married for 20 years by then.

You will have reached Shanghai by this time tomorrow.

They have been married for 20 years by then. p>

You will have arrived in Shanghai by this time tomorrow

Basic usage of present continuous tense:

a. Indicates what is happening now (when the speaker is speaking).

We are waiting for you: We are all waiting for you

b. Habitual progression: Indicates long-term or repetitive actions, which may not be ongoing when speaking.

Mr. Green is writing another novel: Mr. Green is writing another novel

(He is not writing when he speaks, he is only in the state of writing.)

< p>She is learning piano under Mr. Smith: She is learning piano under the guidance of Mr. Smith

c. Verbs expressing gradual changes include: get, grow, become, turn, run, go, begin, etc.

The leaves are turning red: the leaves are turning red

It's getting warmer and warmer: the weather is getting warmer

d. with always, constantly Words such as "forever" are used together to express recurring actions or persistent states, often with a subjective flavor of the speaker.

You are always changing your mind: You always change your mind

Typical examples

My dictionary ___,I have looked for it everywhere but still___ it.< /p>

A. has lost,don't find　B. is missing,don't find　C. has lost,haven't found　D. is missing,haven't found.

Answer D. The previous sentence is a state that is still ongoing. When applied to the progressive tense, since it is not found, its influence still exists. When applied to the perfect tense, the instant verb can be used in the perfect tense when used in the negative form.

Verbs without continuous tense

1) Verbs in fact state

have,belong,possess,cost,owe,exist,include,contain,matter, weigh, measure, continue

I have two brothers: I have two brothers

This house belongs to my sister: This house belongs to my sister

2 ) Verbs of mental states

Know,realize,think,see,believe,suppose,imagine,agree,recognize,remember,want,need, forget, prefer,mean,understand,love,hate

I need your help: I ??need help

He loves her very much: He loves her very much

3) Momentary verb

accept, receive ,complete,finish,give,allow,decide,refuse.

I accept your advice: I accept your advice

4) Coupling verb

seem, remain,lie,see,hear,smell,feel,taste,get,become,turn

You seem a little tired: You look a little tired 1) Concept: Indicates an ongoing state at a certain time in the past or action.

2) The main use of past continuous tense is to describe the background of something happening; when a long action happened, another short action happened.

3) Commonly used time adverbials

this morning, the whole morning, all day yesterday, from nine to ten last evening, when, while

My brother fell while he was riding his bicycle and hurt himself.

My brother fell while he was riding his bicycle and hurt himself.

It was raining when they left the station.

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It was raining when they left the station

When I got to the top of the mountain, the sun was shining.

When I got to the top of the mountain, the sun was shining.

Typical examples

1) Mary ___ a dress when she cut her finger.

A. made　B. is making　C. was making　D. makes< /p>

Answer C. Cutting your finger is something that has happened, so the past tense should be used. At the same time, when expresses the simultaneity of time. Mary provides the background of what happened when she was making clothes, so the past continuous tense is used.

2) As she ___ the newspaper,Granny ___ asleep.

read; was falling　B. was reading; fell　C. was reading; was falling　D. read;fell

read; p>

Answer B. as = when, while in sentence B. means when... When describing the background of an event, use the past continuous; when one long action occurs, another short action occurs. The sentence means: Grandma fell asleep while she was reading the newspaper. The word fell (past tense of fall) in the sentence is a linking verb, followed by an adjective, such as: fall sick. 1) Concept: Indicates a state or action that will be carried out at a certain time in the future, or something that is predicted to happen in the future.

She'll be coming soon.

She will be back soon

I'll be meeting him sometime in the future.

I will meet him some time in the future

Note: The future continuous tense is not used to express will. It cannot be said that I'll be having a talk with her.

2) Commonly used Time adverbials

Soon, tomorrow, this evening, on Sunday, by this time, tomorrow, in two days, tomorrow evening

By this time tomorrow, I'll be lying on the beach.

At this time tomorrow, I will be lying on the beach

The simple present tense replaces the future tense

Time adverbial clause, in a conditional sentence, the clause is used Simple present tense instead of future tense

When, while, before, after, till, once, as soon as, so long as, by the time, if, in case (that), unless, even if, whether, the moment, the minute, the day, the year, immediately

He is going to visit her aunt the day he arrives in Beijing.

As soon as he arrives in Beijing, he will Look at his aunt.