宾语从句是一般疑问时,其引导词有两个“是否”:whether, if。
if的用法稍稍比较有限,如:if引导的宾语从句,不能作介词的宾语;不能与or not 连用;后面不能接
动词不定式;等。
I want to see if he can do it.
I don't know whether he will come or not.
I can’t decide whether to stay.
His father is worried about whether he lose his work .