一道英语问题1.I haven't heard from Bill ? he left here.A.since.B.b

一道英语问题
1.I haven't heard from Bill ? he left here.
A.since.
B.before.
C.when.
D.while.
2.The students put down their pens when the teacher ? them to stop writing.
A.said.
B.spoke.
C.told.
D.talked.
3. ? of us have read the story,but we really know a little about it.
A.None.
B.Both.
C.Some.
D.All.
4.Mr Black didn't teach ? English last tern.Their English teacher was Mr White.
A.their.
B.theirs.
C.them.
D.themselves.
5.Could you tell me when ? .
A.does the train leave.
B.will the train leave.
C.the train has left.
D.the train leaves.
请写出结果并说明理由好吗?