The fact has worried many scientists the earth is becoming warmer and warmer the

The fact has worried many scientists _______ the earth is becoming warmer and warmer these years.

A. what B. which C. that D. though

试题答案

C

分析该句结构可以知道the earth is becoming warmer and warmer these years是The fact的同位语，故而缺少同位语从句的引导词that。