Question

【初中英语】被动语态相关题目

1 I often see him play the piano after school. 改为被动语态

2 They are often heard to sing songs by him next room. 改为主动语态

【课堂中老师讲解的是关于双宾语和to的省略及添加，还有词组在被动语态的变换中作为一个整体而不可拆分的注意事项，还是有些不清楚，希望能针对题目和以上几点来解答，谢谢

Answer 1

1. He is often seen to play the piano after school.
2.He often hears them sing songs next room.
解析：这些动词真奇怪，主动语态省略to,被动语态to 回来。还有以下动词也一样：watch，help,let ,hear,see ,notice等see sb do sth 变为be seen to do sth 也可以记住是固定结构

Answer 2

这不是双宾语

这是复合宾语 即宾语加宾补
动词不定式作宾补时 在有的动词后面 不加to
即
不定式来作宾补
下列词后省略to
“三眼”“两耳”“一感觉”
外加三个“小使役”
“三眼”指see、 watch、 look at
“两耳”指hear、 listen to
“一感觉”指feel
“小使役”指let 、make、 have
在这些动词后的不定式作宾补to 要省去。
例如：
I saw him come .
我看见他来了。
I heard him sing .
我听见他唱歌了。
We felt the house shake
我们感到房子摇动。
Let him do it .
让他做吧。
I would have you know that I am ill .
我向要妮知道我病了。
They made the boy go to bed early .
他们让那男孩早早睡觉去。
注释
在动词find 、help 后不定式做宾补可带to 也可不带to 。

上述感觉动词与使役动词转换为被动结构时，其后的动词不定
式一般须带to 。
如：he was seen to come .
看见他来了。
The boy was let to go to bed early .
让这个男孩早点睡觉。
也就是被动语态中 原来作宾补的不定式 变成了主补 不定式作主补必须带to

所以你的例句1 I often see him play the piano after school. 改为被动语态
答案是he is often seen to play the piano after school.
2 They are often heard to sing songs by him in the next room. 改为主动语态

答案是he often hears them sing songs in the next room.

Answer 3

see doing 表示看见正在做某事
enter是个点动词，要么就进去了，要么就没进，走进办公室还用正在吗？时间极短的。