23. Do not try to repair the computer yourself _____ you are an expert.

　　 A. if　　　 B. that　　 C. unless　 D. because

22. The cars ______ yesterday sell very well.

　　 A. what I saw　　 B. that I see　　 C. what I see　　 D. that I saw

21. Kitty will stay here for ______ to help us.

　　 A. sometime　　 B. sometimes　　 C. some time　 D. some times

20. I don’t know if he ______ me if he ______ free.

　　 A. will help, will be　　 B. helps, is　　　 C. will help, is　　 D. helps, will be

19. They have to work at once, _______?

　　 A. can they　　 B. can’t they　　　 C. don’t they　　 D. haven’t they

18. You ______ to the party if you’re so busy.

　　 A. don’t need come　　 B. not need coming　　　 C. needn’t come　 D. need not to come

17. When something is wrong with your robot, it might ______ in your flat.

　　 A. make a mess　　 B. made a mess　　 C. makes a mess　　 D. made mess

16. The robot can help Mum _________ when there are dirty clothes.

　　 A. does　 the washing　　 B. do the washing　 C. did the washing　 D. doing the washing

15. My computer caught a _________ (病毒) and caused a lot of problems.

14. The robot made Simon’s life much _________. (容易)