4. 随着时间的流逝，他的头发渐渐变得灰白了。

　 As time ___ ___ , his hair is getting grey.

3. 等着他是没用的。他再也不会回来了。

　 ___ ___ ___ ___ 　in waiting for him. He will never return.

2. 如果她发现了你丢了她的手表怎么办？

　 ___ ___ she finds that you have lost her watch?

1. 休息了一会儿，这个科学家继续做研究。

　 The scientist ___ ___ ___ 　his research after a rest.

6.　　　 The two scientists were ____ their research.

5.　　　 When did you ___ Mary?

4.　　　 It really ___ whether you work hard or not.

3.　　　 We must ___ what we do, even when others don’t.

2.　　　 He was away from home for about two years, and he often ____ his mother.

turn out, go by, dream of, get engaged to; be satisfied with; believe in; make a difference

1.　　　 Three years ____, but he still was alone.