同学你好，该知识点来自沪江网校《英语零基础直达大学六级【8月班】》的课程，想要更系统的学习，欢迎进入课程学习。不仅可以和更多的同学一起学习，而且还有老师、助教随时的学习指导和知识点解答哦。

同学你好~
C
1 Yes, I took some (photographs). No, I didn't take any(photographs).
2 Yes, I bought some (bread). No, I didn't buy any (bread).
3 Yes, I saw some (people). No, I didn't see any (people).
D
1 Refrigerators are necessary in hot countries. 无需加the，泛指概念。
2 Which river is the longest, the Nile, the Amazon, or the
Mississippi?
3 Heyerdahl crossed the Pacific on a raft.
4 Why is Britain sometimes called the United Kingdom?
5 We sailed up the Red Sea and then went through the Suez
Canal.

祝同学学习进步~