请看两道中考试题：

1.-How long have you ________ the book?

-Two weeks.

A. bought B. lent

C. had D. borrowed

(2002四川眉山)[Key:C]

2. -Do you know him well?

-Sure, we________friends for ten years.

A. were B. have been

C. have become D. have made

(2002河北)[Key:B]

从考生答卷上看，许多考生都误选了1. A、D 2. C、D。究其原因，是学生对瞬间动词与延续性动词的用法未掌握的缘故。笔者现将这两类动词的含义、用法等作以归纳。

一、瞬间动词和延续性动词的含义及用法

1.瞬间动词是指动作短暂、不长久的动词，如begin, become, sell, buy, borrow等。其用法有：

①有一般时态、进行时态和完成时态。例如：

They began classes at eight this morning.今天上午他们八点钟开始上课的。(一般过去时)

I'm coming, Mum.妈妈，我就来。(现在进行时)

The train hasn't arrived yet.火车还未到达。(现在完成时)

②常与点时间连用。例如：

She often goes to bed at ten.她经常十点钟睡觉。

③不能与段时间连用。例如：

He has joined the army for two years. (×)

She has come here for half an hour. (×)

2.延续性动词是指长久的、可以延续的动词，如sleep, know, keep, wait, study等。其用法为：

①有各种时态。例如：

They knew each other last year.他们去年就彼此相识。(过去时)

We'll learn Russian next year.明年我们要学俄语。(将来时)

②常与段时间连用。例如：

Mr Zhang has lived here for two years.张先生在这儿住了两年了。

He has taught there since 1987.自1987年来他一直在那儿教书。

③不与点时间连用(do, have, eat等除外)。例如：

Mary has worked at eight. (×)

She walked at five yesterday. (×)

二、避免瞬间动词和延续性动词与时间误用的方法

1.避免瞬间动词与段时间误用，可以用以下五种方法：

①用ago这个词。例如：

他买了这本书两年了。

误：He has bought the book for two years.

正：He bought the book two years ago.

②将瞬间动词用相同或相近的延续性动词(短语)代替。例如：

他们认识5年了。

误：They have got to know each other for five years.

正：They have known each other for five years.

③将瞬间动词用意义相同的形容词或分词(副词)短语作表语的形式来代替。例如：

他父亲死了五年了。

误：His father has died for two years.

正：His father has been

dead for two years.

④运用句型It is (has been)…since…来表达。例如：

汤姆参军4年了。

误：Tom has joined the

army for four years.

正：It is (has been) four years since Tom joined the army.

⑤用瞬间动词的否定结构来表达。例如：

直到父母回来他才睡觉。

误：He went to bed until his parents came home.

正：He didn't go to bed until his parents came home.

2.避免延续性动词与点时间状语误用的方法有：

①用延续性动词的进行时态来表达。例如：

昨晚十点钟他正学英语。

误：He studied English at ten o'clock last night.

正：He was studying English at ten o'clock last night.

②在延续性动词前加begin等瞬间性动词来表达。例如：

玛丽8点钟工作。

误：Mary worked at eight o'clock.

正：Mary began to work at eight o'clock.

三、瞬间动词与延续性动词在时间状语从句中的运用

1.在以when, as soon as, as, before, after等引导的时间状语从句中，谓语动词既可以是瞬间性的，也可以是延续性的。例如：

When he came in, I was doing some washing.他进来时，我正在洗衣服。

We often take a nap after we have meal.饭后，我们常常要小睡一下。

2.在以while引导的时间状语从句中，谓语动词只能是延续性的。例如：

While they were working, they saw something strange in the sky.当他们在劳动时，他们看见天空中有些奇怪的东西。

3.在以till, until引导的时间状语从句中，谓语动词既可是瞬间性动词，也可是延续性动词。例如：

①若主句的谓语动词是瞬间动词，句子用否定结构，从句也用瞬间动词。例如：

Mr White didn't leave the workshop until he finished his work.怀特先生直到做完了工作才离开车间。Last night I didn't go to bed until my mother came home.昨晚我母亲下班回家后我才睡觉。

②若主句谓语动词是延续性动词，这时句子用肯定结构和否定结构均可，但含义有差别。试比较：

I worked until she fell asleep.我一直工作到她睡着为止。

I didn't work until she fell asleep.直到她睡着了，我才工作。