英语小镇

20-1 Overview of Basic verb forms used in conditional sentences
Situation	if- clause	Result Clause	Examples
True in the present/future	simple present	simple present	If I have enough time, I watch TV every evening.
		will + simple form	If I *have* enough time, I *will watch* TV later on tonight.
Untrue in the present/ future	simple past	would + simple form	If I had enough time, I *would* watch TV now or later on.
Untrue in the past	past perfect	would have + past participle	If I *had had* enough time, I *would have* *watched* TV yesterday.
20-2 True in The Present or Future
(a) If I don't eat breakfast, I always get hungry during class. (b) Water freezes or will freeze if the temperature reaches 32°F/10°C. (c) If I *don't eat* breakfast tomorrow morning, I *will get hungry during class. (d) If it rains,* I should stay home. If it rains, I *might decide* to stay home. If it rains, we *can't go.* If it rains, *we're going to stay* home. (e) If anyone calls, please take a message.-		In conditional sentences that express true, factual ideas in the present/ future, the simple present (not the simple future) is used un the if-clause. The result clause has various possible verb forms. A result clause verb can be: 1. the simple present, to express a habitual activity or situation as in (a). 2. either the simple present or the simple future, to express an established, predictable fact or general truth, as in (b). 3. the simple future, to express a particular activity or situation in the future, as in (c). 4. modals and phrasal modals such as should, might, can, be going to, as (d). 5. an imperative verb, as in (e).
(f) If anyone *should call*, please take a message.		Sometimes *should* is used in an if-clause. It indicates a little more uncertainty than the use of the simple present, but basically the meaning of examples (e) and (f) is the same.

20-3 Untrue (contrary to Fact) in the present
(a) If I taught this class, I would give tests. (b) If he were here right now, he *would help* us. (c) If I were you, I *would accept* their invitation.		In (a): In truth, I don't teach this class. In (b): In truth, he is not here right now. In (c): In truth, I am not you. Note: *Were* is used for both singular and plural subjects. *Was* (with I, he, she, it) is sometimes used in informal. Speech: If I *was* you, I'd accept their invitation.
Compare: (d) If I had enough money, I would buy a car. (e) If I had enough money, I *could buy* a car.		In (d): The speaker wants a car, but doesn't have enough money. *Would* expresses desired or predictable results. In (e): The speaker is expressing one possible result. *Could* = would be able to. *Could* expresses possible options.
20-4 Untrue in the past
(a) If you had told me about the problem, I *would have helped* you. (b) If they *had studied, they would have passed* the exam. (c) If I hadn't slipped on the stairs, I *wouldn't have broken* my arm.		In (a): In truth, you did not tell me about it. In (b): In truth, they did not study. Therefore, they failed the exam. In (c): In truth, I slipped on the stairs, I broke my arm. Note: The auxiliary verbs are almost always contracted in speech, "if you'd told me, I would've helped you.
Compare: (d) If I had had enough money, I would have bought a car. (e) If I had had enough money, I could have bought a car.		In (d): *would* expresses a desired or predictable result. In (e): *could* expresses a possible option; could have bought = would have been able to buy.
20-5 Using Progressive Verb Forms in Conditional Sentences
(a) True: It is raining right now, so I will not go for a walk. (b) Conditional: If it were not raining right now, I would go for a walk. (c) True: I am not living in Chile. I am not working at a bank. (d) Conditional: If I were living in Chile, I would be working at a bank. (e) True: It *was raining* yesterday afternoon, so I did not go for a walk. (f) Conditional: If it had not been raining, I would have gone for a walk. (g) True: I was not living in Chile last year, I *was not working* at a bank. (h) Conditional: If I *had been living* in Chile last year, I *would have been working* at a bank.
20-6 Using "Mixed Time" In Conditional Sentences
Frequently the time in the if- Clause and the time in the result clause are different: one clause may be in the present and the other in the past. Notice that past and present times are mixed in these sentences.
(a) True: I *did not eat* breakfast several hours ago, so I am hungry now. (b) Conditional: If I *had eaten* (past) breakfast several hours ago, I *would not be* (present0 hungry now. (c) True: He *is not* a good student. He did not study for the test yesterday. (d) Conditional: If he *were* (present) a good student, *he would have* (past) studied for
20-7 Omitting if
(a) *Were I* you, I wouldn't do that . (b) *Had I known,* I would have told you. (c) *Should anyone call,* please take a message.		With *were, had* (past perfect), and *should,* sometimes if is omitted and the subject and verb are inverted. In (a): *Were I you* = If I were you. In (b): Had I known= If I had known. In (c): *Should anyone* = If anyone should call.
20-8 Implied Conditions
(a) I *would have gone* with you, but I had to study. (b) I never *would have succeeded* without you help. (c) She ran; otherwise, she would have missed her bus.		Often the if-clause is implied not stated. Conditional verbs are still used in the result clause. In (a): the implied condition: if I hadn't had to study. In (b): the implied condition: if you hadn't helped me. Conditional verbs are frequently used following *otherwise. In (c): the implied if-* clause = if she had not run.
20-9 Using as If/ As though
(a) It looks like rain. (b) It looks as if it is going to rain. (c) It looks as though it is going to rain. (d) It looks like it is going to rain. (informal)		Notice in (a): *like* is followed by a noun object. Notice in (b) and (c): *as if* and *as though* are follow ed by a clause. Notice in (d): *like* is followed by a clause. This use of like is common in informal English, but is not generally considered appropriate in formal English; *as if* or as though is preferred (a), (b), and (d) all have the same meaning.
True Statement		Verb form After as if/As though
(e) He is not a child. (f) She *did not take* a shower with her clothes on. (g) He *has met* her. (h) She *will be* here.		• She talked to him as if he *were* a child. • When she came in from the rainstorm, she looked as if she *had taken* a shower with her clothes on . • He acted *as though* he *had never met* her. • She spoke *as if* she *wouldn't be* here.
Usually the idea following *as if/as though* is "untrue", In this case, verb usage is similar to that in conditional sentences.

20-10 Verb Forms Following wish
Wish is used when the speaker wants really to be different, to be exactly the opposite. A wish about the future:
True Statement	Verb form following wish
(a) She *will not tell* me. (b) He isn't going to be here. (c) She *can't come* tomorrow.	• I wish (that) she would tell me. • I wish he *were going to be* here. I wish she *could come* tomorrow.
A wish about the present:
(d) I *don't know* French. (e) I t *is raining* right now. (f) I *can't speak* Japanese.	I wish I *knew* French. I wish it *weren't raining* right now. I wish I *could speak* Japanese.
A wish about the past
(g) John didn't come. (h) Mary couldn't come.	I wish John had come I wish Mary could here come.
Wish is following by a noun clause, past verb forms, similar to those in conditional sentences, are use in the noun For example, in (a): *would, the past form of will, is used to make a wish about the future. In (d): the simple past (knew) is used to make a wish about the present. In ((g): the past perfect (had come*) is used to make a wish about the past.
*20-11 Using would* to make wishes about the future**
(a) It is raining. I wish it would stop. ( I want it to stop raining.) (b) I'm expecting a call. I wish the phone *would ring.* (I want the phone to ring.) (c) It's going to be a good party. I wish you would come. (d) We're going to be late. I wish you would hurry.	Would is usually used to indicate that the speaker wants something to happen or someone other than the speaker to do something in the future. The wish may or may not come true (be realized). In (c) and (d): I wish you would... is often used to make a request.

1 2 3 4 [5]

Hosted by www.Geocities.ws