20.We must that the experiment is controlled as rigidly as possible.

40.It did not stop rainingthe football match was over.

39.Hardly had Jerry got to the officehis wife called him for an emergency at home.

38.The teacher used a microphone his voice could reach the back of the room.

37.John puts up his handthe teacher asks a question.

36.He wrote down Jane＇s phone numberhe could remember it.

35.Literature must consist of words, music must consist of sounds.

34.It was ten o＇ clock he came back.

33.You can fly to London this eveningyou don＇t mind changing planes in Paris.

32.I＇d like to see him in my officehe arrives.

31.you decide to take up, you should try to make it a success.