.________, I have never seen anyone who’s as capable as John. 

—Was it by cutting down staff      are not diligent enough       she saved the firm?—No, it was by improving work efficiency．

Following the girl, we went into a hall, on ____ walls hung a few pictures of some famous scientists．

Ms. Claire is a strict but kind teacher, _____ who, usually, _____ her students.

He took medicine 3 times a day,________ didn't work.