31.眾所周知，指南針首先是中國制造的。(As)

32. 我們需要更多的練習(xí)是十分清楚的。(practice)

33. 你沒聽李老師的報(bào)告真是太遺憾了。(miss)

34. 碰巧我那天晚上有空。(happen)

35. 據(jù)提議試驗(yàn)應(yīng)該在低溫下做。(suggest)

36. 他已經(jīng)做的事情與我們無關(guān)。(nothing)

37. 她問我花了多長時(shí)間建成這座大橋。(take)

38. 直到昨天我才知道他要來。(not… until)

39. 這城市不像三年前的那樣子了。(used)

40. 這正是你要尋找的東西。(look)

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

32. That we need more practice is quite clear.

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

34. It happened that I was free that evening.

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

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

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

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

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

40. This is what you are looking for.