Question

(2013·安徽，21)From space, the earth looks blue.This is ________about seventy－one percent of its surface is covered by water.

A．why B．how C．because D．whether

 

Answer 1

C

【解析】考查名词性从句。此处考查表语从句。根据句意：地球看起来是蓝色的。这是因为其表面71%是被水覆盖的。