The Mekong River Commission has found no evidence the dams on the upper reaches have an in

问题补充：

The Mekong River Commission has found no evidence the dams on the upper reaches have an influence on the water flow downstream.

A. that

B. which

C. where

D. what

答案：

(答案→)A. that

B. which

C. where

D. what

解析：句意：湄公河委员会发现没有证据表明上游的水坝对下游的水流量有影响。evidence后接的是同位语从句，that在句子中不做成分也没有意思，只对evidence进行解释说明。