英语句型转换题.1、We didn't go out for a walk because it was raining

英语句型转换题.
1、We didn't go out for a walk because it was raining.（变为简单句）
We didn't go out for a walk _____ _____ the rain.
2、I don't know when we will begin the work.（变为简单句）
I don't know _____ _____ _____ the work.
3、You must finish all the work before you go to bed.（变为简单句）
You must finish all the work _____ _____ to bed.