To finish the homework he spent four hours in the study.A. lockingB. lockedC. locked him

问题补充：

To finish the homework, he spent four hours in the study.

A. locking

B. locked

C. locked himself

D. to lock

答案：

A. locking

(答案→)B. locked

C. locked himself

D. to lock

解析：考查非谓语动词。句中逻辑主语为he，与lock之间的关系为被动，故用过去分词。句意：为了完成家庭作业，他花了四个小时把自己关在书房里。