题目内容：

如题
Most parents encourage their children to take an active part in social events,_____ those events do not interfere with their studies.
A lest B unless
C though D provided
我选的B 难道不对?
我不懂,感觉选它意思不通顺啊.

优质解答

大多数家长鼓励他们的孩子参加一些社会实践活动,如果这些活动不影响他们的学习的话.
UNLESS是如果不,除非
PROVIDED是倘若,如果