is even more important is              the earth cooled down, water began t

题型：不详难度：来源：

     is even more important is              the earth cooled down, water began to appear on its surface.

A．When; that; when

B．What; whether; as

C．What; that; as

D．lt; whether; as

答案

C

解析

这题考查从句的用法，第一空填what做主语从句，在主语从句中what做主语，第二空填that引导表语从句，在表语从句中，as是引导时间状语从句，句意是：甚至更重要的是：随着地球的冷却，水开始出现在表面。选C。