语言教学 | 普渡大学写作教学系列General Writing 73-Grammar(14)：Verb Tenses(1)

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Introduction to Verb Tenses

Only two tenses are conveyed through the verb alone: present (“sing") and past (“sang"). Most English tenses, as many as thirty of them, are marked by other words called auxiliaries. Understanding the six basic tenses allows writers to re-create much of the reality of time in their writing.

Simple Present: They walk.

Present Perfect: They have walked.

Simple Past: They walked.

Past Perfect: They had walked.

Future: They will walk.

Future Perfect: They will have walked.

Usually, the perfect tenses are the hardest to remember. Here’s a useful tip: all of the perfect tenses are formed by adding an auxiliary or auxiliaries to the past participle, the third principal part.

1st principal part (simple present): ring, walk

2nd principal part (simple past): rang, walked

3rd principal part (past participle): rung, walked

In the above examples, will or will have are the auxiliaries. The following are the most common auxiliaries: be, being, been, can, do, may, must, might, could, should, ought, shall, will, would, has, have, had.

Present Perfect

The present perfect consists of a past participle (the third principal part) with "has" or "have." It designates action which began in the past but which continues into the present or the effect of which still continues.

1. Simple Past: “Betty taught for ten years.” This means that Betty taught in the past; she is no longer teaching.

2. Present Perfect: “Betty has taught for ten years.” This means that Betty taught for ten years, and she still teaches today.

1. Simple Past: “John did his homework so he can go to the movies.” In this example, John has already completed his homework.

2. Present Perfect: “If John has done his homework, he can go to the movies.” In this case, John has not yet completed his homework, but he will most likely do so soon.

Present Perfect Infinitives

Infinitives also have perfect tense forms. These occur when the infinitive is combined with the word “have.” Sometimes, problems arise when infinitives are used with verbs of the future, such as “hope,” “plan,” “expect,” “intend,” or “want.”

I wanted to go to the movies.

Janet meant to see the doctor.

In both of these cases, the action happened in the past. Thus, these would both be simple past verb forms.

Present perfect infinitives, such as the examples below, set up a sequence of events. Usually the action that is represented by the present perfect tense was completed before the action of the main verb.

1. I am happy to have participated in this campaign! The current state of happiness is in the present: “I am happy.” Yet, this happiness comes from having participated in this campaign that most likely happened in the near past. Therefore, the person is saying that he or she is currently happy due to an event that happened in the near past.

2. John had hoped to have won the trophy. The past perfect verbal phrase, “had hoped,” indicates that John hoped in the past, and no longer does. “To have won the trophy” indicates a moment in the near past when the trophy was still able to be won. Thus, John, at the time of possibly winning the trophy, had hoped to do so, but never did.

Thus the action of the main verb points back in time; the action of the perfect infinitive has been completed.

Past Perfect

The past perfect tense designates action in the past just as simple past does, but the past perfect’s action has been completed before another action.

1. Simple Past: “John raised vegetables.” Here, John raised vegetables at an indeterminate time in the past.

2. Past Perfect: “John sold the vegetables that he had raised.” In this sentence, John raised the vegetables before he sold them.

1. Simple Past: “Renee washed the car when George arrived.” In this sentence, Renee waited to wash the car until after George arrived.

2. Past Perfect: “Renee had washed the car when George arrived.” Here, Renee had already finished washing the car by the time George arrived.

In sentences expressing condition and result, the past perfect tense is used in the part that states the condition.

1. If I had done my exercises, I would have passed the test.

2. I think Sven would have been elected if he hadn't sounded so pompous.

Further, in both cases, the word if starts the conditional part of the sentence. Usually, results are marked by an implied then. For example:

If I had done my exercises, then I would have passed the test.

If Sven hadn’t sounded so pompous, then he would have been elected.

Again, the word then is not required, but it is implied.

Future Perfect

The future perfect tense is used for an action that will be completed at a specific time in the future.

1. Simple Future: “On Saturday, I will finish my housework.” In this sentence, the person will finish his or her housework sometime on Saturday.

2. Future Perfect: “By noon on Saturday, I will have finished my housework.” By noon on Saturday, this person will have the housework already done even though right now it is in the future.

1. Simple Future: “You will work fifty hours.” In this example, you will work fifty hours in the future. The implication here is that you will not work more than fifty hours.

2. Future Perfect: “You will have worked fifty hours by the end of this pay period.” By the end of this pay period, you would have already worked fifty hours. However, as of right now, this situation is in the future. The implication here is that you could work more hours.

Review

1. Judy saved thirty dollars. (past—the saving is completed)

2. Judy will save thirty dollars. (future—the saving has not happened yet)

3. Judy has saved thirty dollars. (present perfect—the saving has happened recently)

4. Judy had saved thirty dollars by the end of last month. (past perfect—the saving occurred in the recent past)

5. Judy will have saved thirty dollars by the end of this month. (future perfect—the saving will occur in the near future, by the end of this month)

Passive Verbs

Often, writing teachers encourage the use of action verbs and active voice. However, there are times when it makes more sense to use passive verbs instead.

Use passive verbs when you do not want to specify the actor. If the actor is either unknown or irrelevant, you may not want to specify an actor: “Crimes were committed.” In this case, the actor’s name is purposely avoided.

Additionally, use passive verbs when you wish to foreground a topic that is not the action or actor. “Penicillin was developed in 1928.” In this case, penicillin is foregrounded instead of the developer and instead of the verb, developed.

In the active example of simple present tense, the company ships the computers. Here, the company is doing the action.

In the passive example of simple present tense, computers are foregrounded instead of the company. In this case, it doesn’t matter who sent the computers.

In the active example of present progressive tense, the factors of the storm are emphasized rather than the storm itself.

In the passive example of present progressive tense, the storm is focused on rather than the factors of the storm.

Use the passive voice if you do not wish to detail the factors of the storm and instead wish to present the storm as the focus of the sentence.

In the active example of the future tense, the representative is specified as the person who will pick up the computer. In this case, the owners of the computer know to look out for a specific person who represents this company.

In the passive example of the future tense, we do not know who will pick up the computer, just that it will be picked up.

Use passive voice if you do not want to specify who will pick up the computer.

In the active voice example of the modal verb, the second person pronoun, you, is directly addressed as the person who can use the computer.

In the passive voice example of the modal verb, no single person is addressed. Therefore, the computer can be used by anyone.

Active Verb Tenses