使役、感官等特殊动词的常见用法
一、have , let与make ,四看二听一感觉，只得最好加情愿。

A.（四看：see，watch, look at , notice .二听hear, listen to .
一感觉：feel ，只得：have to ，最好：had better ，
情愿：would like to ）+V-原 . 例如：
<1> Mr. zhang has us do a lot of homework every day.张老师每天要求我们做很多作业。

<2> I let him go. 我让他走开。

<3> The news made her feel happy.这个消息使她很高兴。

<4> I saw him enter the room.我看见他进了那个房间
<5> I heard her sing in her room a few minutes ago.几分钟前我听到她在屋里唱歌了。

B. 以上感官动词和使役动词等在主动语态中后面跟V-原，但当他们被用于被动语态中时，后面就要跟to +
V-原。

例如：
<1>He was seen to enter the room.
<2>She was made to feel happy by the great news.
<3>She was heard to sing in her room a few minutes ago.
[注意]：上面的感官动词（四看、二听）后面虽然通常跟V-原，但有时也可跟动名词即V-ing . 其区别是：
a.感官动词（四看、二听）+ V-原: 表示看见或听见某人做了某事的全过程, 强调过程(看见了全过程)。

b.感官动词（四看、二听）+ V-ing ：表示看见或听见某人正在做某事，强调动作（正在进行）。

例句：
<a> I often hear the girl play the piano in the next room. 我常常听见这个女孩在隔壁弹钢琴
<b> I heard the girl playing the piano at this time yesterday. 我昨天这个时候听见这女孩正在弹钢琴。

<a> I saw her go across the street. 我看见她过了马路
<b> I saw her going across the street. 我看见她正在过马路.。