英語(yǔ)中的幾種時(shí)態(tài)在一定情況下可以互相轉(zhuǎn)換，以下是幾種常見的轉(zhuǎn)換形式：

一、一般過去時(shí)與現(xiàn)在完成時(shí)的轉(zhuǎn)換

在現(xiàn)在完成時(shí)中，延續(xù)性動(dòng)詞能與表示一段時(shí)間的狀語(yǔ)連用，瞬間動(dòng)詞卻不能。但是，可用別的表達(dá)方式：①瞬間動(dòng)詞用于“一段時(shí)間 + ago”的一般過去時(shí)的句型中；②瞬間動(dòng)詞可改成與之相對(duì)應(yīng)的延續(xù)性動(dòng)詞及短語(yǔ)，與一段時(shí)間連用；③瞬間動(dòng)詞用于“It is + 一段時(shí)間 + since + 一般過去時(shí)”的句型中，表示“自從……以來有……時(shí)間”的意思，主句一般用it is來代替It has been;④瞬間動(dòng)詞用于“Some time has passed since + 一般過去時(shí)”的句型中。請(qǐng)看：

A. He joined the League two years ago.

B.He has been in the League for two years.

C. It is two years since he joined the League.

D. Two years has passed since he joined the League.

二、一般現(xiàn)在時(shí)與現(xiàn)在進(jìn)行時(shí)的轉(zhuǎn)換

在一般現(xiàn)在時(shí)中，at加上名詞表示“處于某種狀態(tài)”，如at work（在工作）, at school（上學(xué)、上課）等。此短語(yǔ)可與進(jìn)行時(shí)態(tài)轉(zhuǎn)換。請(qǐng)看：

Peter is at work, but Mike is at play.

Peter is working, but Mike is playing.

三、現(xiàn)在進(jìn)行時(shí)與一般將來時(shí)的轉(zhuǎn)換

在現(xiàn)在進(jìn)行時(shí)態(tài)中g(shù)o, come, leave, start, arrive等動(dòng)詞常與表示將來的時(shí)間狀語(yǔ)連用表示將要發(fā)生的動(dòng)作。如：I am coming, Mum! 意為“我就來，媽媽！”請(qǐng)看：

The train is leaving soon.

The train will leave soon.

四、“be going to+動(dòng)詞原形”與“will(shall)+動(dòng)詞原形”結(jié)構(gòu)的轉(zhuǎn)換

“be going to+動(dòng)詞原形”、表示打算、計(jì)劃要做的事；將來時(shí)“will(shall)+動(dòng)詞原形”結(jié)構(gòu)在書面語(yǔ)中，當(dāng)主語(yǔ)為第一人稱時(shí)，常用助動(dòng)詞shall。在口語(yǔ)中，所有人稱都可以用will。請(qǐng)看：

We are going to visit the Great Wall next Sunday.

We shall visit the Great Wall next Sunday.