过去完成时when 、before、after造句每个一句,要翻译,

I had been at the bus stop for 20 minutes when a bus finally came.
当车来的时候，我在车站已等了20分钟。
After he arrived in England, Marx worked hard to improve his English.
马克思到达英格兰之后，努力提高他的英语水平。
They had planted six hundred trees before last Wednesday
在上个星期三之前他们种了六百棵树

he is sleep,when I back home.
she went out, before I back home.
she goes out, after I back home.

句型一：过去完成时+when+一般过去时 如：
I had finished my homework when Mum came back.妈妈回来的时候,我已经完成我的作业了.
句型二：过去完成时+before+一般过去时 如：
I had finished my homework before Mum came back.妈妈回来之前,我已经完成我的作业了.
句型三：after+过去完成时+一般过去时 如：
After I had finished my homework,Mum came back.我已经完成我的作业之后,妈妈才回来.

I had finished my homwork when she called me.她给我打电话时我已经完成了作业。
The train had left before I got there.在我到达之前火车就开走了。
I left the shop after I had bought what I want.买到想买的东西后，我离开了商店。