1.I have a lot of books, half of ________ novels.
A. which B. that C. whom D. them
解析：half of them novels 为独立主格结构，相当于 and half of them are novels。
2. ________ more and more forests destroyed, many animals are facing the danger of dying out.
A. because B. as C. With D. Since
解析：考查“with + 名词 + 过去分词”结构。
3. The bus was crowded with passengers going home from market, most of ________ carrying heavy bags and baskets full of fruit and vegetables they had bought there.
A. them B. who C. whom D. which
解析：most of them carrying...为独立主格结构，相当于 and most of them were carrying...，也可改为：most of whom were carrying。注意改动后连词 and 的使用和动词 were的使用。
4. The largest collection ever found in England was one of about 200,000 silver pennies, all of ________ over 600 years old.
A. which B. that C. them D. it
解析：all of them over 600 years old 为独立主格结构，相当于 and all of them are over 600 years old。
5. The cave ________ very dark, he lit some candles ________ light.
A. was; given B. was; to give
C. being; given D. being; to give