Tom got all A’s he spent most of his time studying.A. ifB. beforeC. becauseD. although

问题补充：

Tom got all A’s he spent most of his time studying.

A. if

B. before

C. because

D. although

答案：

A. if

B. before

(答案→)C. because

D. although

解析：本题的含义是汤姆取得了好成绩，因为他把大部分时间花费在学习上。本题表示的是因果关系，在原因状语前可用because，故本题选C。