1 -Who should be responsible for the accident?

1 -Who should be responsible for the accident?
-The boss,not the workers.They just carried out the order （as told) 为什么不能选“as they told"?
2 Let's learn to use the problem we are facing(as)a stepping stone to future success
为什么是as?有什么规定吗？
3 Leave your key with a neighbor (in case) you lock yourself out one day
为什么是”in
4 peter received a letter just now (saying) his grandma would come to see him soon
填says 可不可以？
5 The fact that she never apologized (says) a lot about what king of person she is
为什么填 “says”？
6 The growing speed of a plant is influenced by a number of factors,(most of which) are beyond our control.which 是什么用法？为什么不能是“most of them"?
7 When (we are )asked,he gave good advice 括号内不应是过去时吗？
8 I haven't seen Ann for (so)long that I've forgotten what she looks like.
可不可以是”too"?