9601-40 9608 两道题

jackiehuhu

40.  For thousands of years, people have used some kind of

refrigeration cooling beverages and preserve edibles.     

这题动词时态一致我知道，但为什么不用kinds  而用kind?

9608

19. A coral reef, a matricate aquatic community of plants and animals, is found only in warm, shallow, sunlit seas.

不懂

39. The nitrogen makes up over 78 percent of the Earth's atmosphere, the gaseous mass surrounding the planet.

冠词为何错？

真老九

40。  some kind of表示某一种（不特定的）

19.   a>>an ，intricate的发音开头字母为元音

39。 化学元素之前不用加冠词，也可以说零冠词

jackiehuhu

谢谢斑竹指点