We should plant more trees on sides of the street.A. eitherB. bothC. allD. each

问题补充：

We should plant more trees on sides of the street.

A. either

B. both

C. all

D. each

答案：

A. either

(答案→)B. both

C. all

D. each

解析：either表示任何一个都 both两个都al所有都 each每个都,根据题意,我们应该在这条街两边都种上更多的树.故选B.