【题目】He began to __________ because every means _______ tried already.
A. lose heart; has been B. lose heart; had been
C. lose his heart; was D. lose his heart; had
在线课程【答案】B
【解析】考查动词词组，时态与语态，句意：他开始失去信心了，因为每种方法都已经试过了，lose heart心灰意冷，丧失信心，中间不能加物主代词或冠词；根据句意可知尝试方法是在丧失信心之前，即“过去的过去”发生的事情，故要用过去完成时态，同时要注意使用被动语态，故选B。