参考答案：

　　1. The climate here is as good as that of Kunming.

　　2. She no longer talks and laughs as she used to.

　　3. The more we know the world, the more successful we will be.

　　4. As long as we don’t lose heart, we’ll find a way to overcome the difficulty.

　　5. Whoever does it makes no difference.

　　6. Once she started to dance, she forgot about the time.

　　7. The mountain is so high that I can not climb up to its top.

　　8. On condition that you practise speaking English all the time, you’ll certainly master it very soon.

　　9. The Yangtse River, which we visited last summer, is the longest river in China.

　　10. Have you seen the girl whose composition we discussed yesterday?

　　11. As is known to all, the compass was first made in China.

　　12. That we need more practice is quite clear.

　　13. It is a pity that you missed the lecture made by Teacher Li.

　　14. It happened that I was free that evening.

　　15. It is suggested that the experiment should be made under low temperature.

　　16. What he has done has nothing to do with us.

　　17. She asked me how long it had taken to build the bridge.

　　18. It was not until yesterday that I knew he was coming.

　　19. The city isn’t what it used to be three years ago.

　　20. This is what you are looking for.