---What do you think of your teachers?

---Sometimes they are too strict __________ us _________ our study.

A．at, with

B．at, in

C．with, at

D．with, in

牵引变电所馈线多数故障是暂时性的，采用（）装置后，可大大提高供电可靠性。

A.自动重合闸

B.自投

C.控制

D.跟踪