单选题 There are lots of trees ______ the river.
A. in either side of B. in either sides of
C. on either sides of D. on either side of

【正确答案】 D

【答案解析】[解析] 本题考查介词短语。河岸(bank)需要用介词on；either后面一般接可数名词的单数，故选项D为正确答案。
[避错指南] 干扰项为选项C。on either side of相当于on both sides of，跟名词复数用both。