27. He made a mistake, but then he corrected the situation _____ it got worse.

　A. until　 B. when　 C. before D. as

26.( ---- How far apart do they live?

---- ____I know, they live in the same neighbourhood.

　A. As long as　 　　　　　 B. As far as　 C. As well as　　　　 D. As often as

25. (A good storyteller must be able to hold his listeners' curiosity _______ he reaches the end of the story.

　A. when 　B. unless　 C. after　 D. until

24. Don' t be afraid of asking for help _____ it is needed.

A. unless　 B. since　 C. although　 D. when

23. Mr Hall understands that ____ maths has always been easy for him, it is not easy for the students.

　A. unless　 B. since　 C. although 　D. when

22. (Sally worked late in the evening to finish her report _____ her boss could read it first next morning.

　A. so that 　B. because　 C. before 　D. or else

21. (It was an exciting moment for these foot-ball fans this year, ____ for the first time in years their team won the World Cup.

　A. that　 　B. while　 C. which 　D. when

20. (---- Was his father very strict with him when he was at school ?

---- Yes. He had never praised him _____ he became one of the top students in his grade.

A. after 　B. unless　 　C. until　 D. when

19. You will succeed in the end __ you give up halfway.

A. even if 　B. as though C. as long as D. unless

18. (The famous scientist grew up __ he was born and in 1930 he came to Shanghai.

　A. when B. whenever　 C. where　 D. wherever