使用被動(dòng)語態(tài)的五種情況

被動(dòng)語態(tài)的使用主要見于以下幾種情況：

1. 語義的需要：當(dāng)不知道或沒有必要指出動(dòng)作的執(zhí)行者時(shí)，常用被動(dòng)語態(tài)，這時(shí)往往不用by短語。如：

The front window in the classroom was broken yesterday. 昨天，教室的前窗被打破了。(不知誰打破的)

They have been poorly paid.他們的工資太低。(沒必要指出工資是誰付的)

2. 強(qiáng)調(diào)的需要：突出或強(qiáng)調(diào)動(dòng)作的承受者，如果需要說出動(dòng)作的執(zhí)行者，用by短語。如：

The time-table has been changed .時(shí)間表已變動(dòng)了。(要突出的是“時(shí)間”)

These books are written especially for children.這些書是專門為孩子們寫的。(強(qiáng)調(diào)的是“這些書”)

3. 交際的需要：為了使語言得體或圓滑等不愿意說出動(dòng)作的執(zhí)行者。如：

You are requested to make a speech at next meeting.請(qǐng)您在下次會(huì)議上作個(gè)發(fā)言。

It is said that she is going to be married to a foreigner.據(jù)說她要嫁給一個(gè)外國人。

4. 修辭的需要：出于修辭的原因，或是說為了更好地安排句子。如：

It is generally considered impolite to ask one’s age, salary, marriage, etc.. 問別人的年齡、工資、婚姻狀況等通常被認(rèn)為是不禮貌的。

The notion is especially opposed to by those who have invested much in the area. 這個(gè)提議特別遭到了那些在本地區(qū)投資很大的人的反對(duì)。(因those的定語太長了，若用它作主語，主語與謂語就相距太遠(yuǎn)而顯得句子松散。)

5. 語體的需要：在新聞報(bào)道中，為了表明報(bào)道的客觀性而避免主觀性的透露時(shí)。如：

A car accident happened on the high way this morning. Three men were killed, the wounded were taken away to hospital at once and policemen were sent there to cope with the event. 今天早晨高速公路上發(fā)生了一起車禍，三人喪生，傷員馬上被送往了醫(yī)院，并馬上派了警察去處理這一事件。

另外，在科技論文中，常使用被動(dòng)語態(tài)來強(qiáng)調(diào)客觀事實(shí)。如：

When it is cold enough, water will be turned into ice. 當(dāng)天氣足夠冷時(shí)，水就會(huì)變成冰。

So far, the moon has been visited by earthmen several times. 到目前為止，地球人已經(jīng)幾次拜訪了月亮。