4. However hard he works, he makes little progress.

　 ______ ________ how hard he works, he makes little progress.

3. When he worked, the door was locked.

　 He worked _______ _______ _______ ________.

2. You helped me with my homework. You are kind indeed.

　 ______ very kind _____ you to help me with my homework.

1. It’s time that we went for a walk.

　 It’s time ______ _____ to go for a walk.

20. It would be very safe if you _______ the door ________ to the garden.

A. fasten; led　 B. will fasten; leads C. fastened; leading D. fastened; to lead

19. ________ happened to be no one in the house when the fire broke out.

　 A. It　　　　　 B. This　　　　　 C. There　　　　　　 D. I

18. The question was not as simple as it ________.

　 A. supposes to　　 B. supposed to be　　 C. was supposing to be　 D. was supposed to be

17. ________ a reply, he decided to write again.

　 A. Not receiving　 B. Not having received　　 C. Receiving not　　 D. Having not received

16. I went to meet him at the airport but I ________.

　 A. didn’t　　　 B. failed　　　 C. can’t　　　　　 D. lost

15. There was no ______ about it that they had got the news.

　 A. affair　　　 B. doubt　　　 C. matter　　　　　 D. problem