Question

We are wondering ________ we can prevent people from polluting the earth.

A．who

B．that

C．whether

D．what

Answer 1

C

考查引导词。句意“我们想知道我们能否阻止人们污染地球。”who“谁”；that引导宾语从句，无意义；whether“是否”；what“什么”。故选C。