关于悬垂结构性的改错.

关于悬垂结构性的改错.
2.Though received late at night,he started to work on
the document immediately.
答案是改为Though he received the document late at night,he started to work on it immediately.
而我改为 Received late at night,he started to work on the document immediately.
4.Reading the letter a second time,the meaning becomes
clearer.
When you read…
而我改为 I reading the letter a second time,the meaning becomes clearer to me.
我这样该可以吗?我认为这是独立性结构
5.Reading the instructions repeatedly ,what he meant became clear to me
Reading the instructions repeatedly,I became
clear about what he meant
而我改为 I reading the instructions repeatedly ,what he meant became clear to me
同上一个原理
.7.The teacher walked behind the kids eating their
lunches.这句话,改为直接在the kids前加上逗号 ,
8.While cleaning his gun,it went off
unexpectedly.
答案该为he was cleaning
而我改的是 he cleaning his gun,it went off unexpectedly
就是我的改法 可以吗,如果是错的,为什么呢?有点长,