There are many trees on side of the road and sides of the river.A. both both B. either

问题补充：

There are many trees on side of the road and sides of the river.

A. both, both B. either, either C. either, both

答案：

解析：both两者都，后面的名词side用复数sides, either两者之一，后面的名词用单数side.故选C