—What do you think of the two backpacks? — of them are very nice.A. EitherB. BothC. EachD.

问题补充：

—What do you think of the two backpacks? — of them are very nice.

A. Either

B. Both

C. Each

D. All

答案：

A. Either

(答案→)B. Both

C. Each

D. All

解析：考查点：代词的辨析。解题思路：either “（两者中）任意一个”，both“（两者）都”，each “（三者或者三者以上的）任意一个”，all “（三者或者三者以上）都”，根据答句中用be动词are，故做主语的是复数，问句指的是two backpacks。故选B。