20.“Harry was compelled to resign and to come down to London, where he set up as an army coach.” The relative clause in the sentence serves to（ ）.

50.Firms that use computers have found that the number of staff（ ）is needed for quality control can be substantially reduced.

49.All of us would have enjoyed the party much more if there（ ）quite such a crowd of people there.

48.You（ ）Jim anything about it. It was none of his business.

47.I was very much put（ ）by Mark’s rude behavior; it really annoyed me.

46.My mother can’t get（ ）because she has rheumatism.

45.There（ ）nothing more for discussion, the meeting came to an end half an hour earlier.

44.Do help yourself to some fruit,（ ）you?

43.The central provinces have floods in some years, and（ ）.

42.This is an illness that can result in total blindness（ ）left untreated.

41.Acute hearing helps most animals sense the approach of thunderstorms long before people（ ）.