(·高考安徽卷)From space the earth looks blue.This is about seventy­one percent of its

问题补充：

(·高考安徽卷)From space，the earth looks blue.This is about seventy­one percent of its surface is covered by water.

A. why

B. how

C. because

D. whether

答案：

A. why

B. how

C. because

D. whether

解析：选C。本题考查表语从句的引导词。句意：从太空看，地球是蓝色的。这是因为它表面大约71%被水所覆盖。首先分析前后两句之间的逻辑关系，此处为“前果后因”，使用because，故选C项。because和why均可引导表语从句，解题时要弄清前后句之间的逻辑关系——是“前因后果”还是“前果后因”。“前因后果”使用why，“前果后因”使用because。