是 反问疑问句
can,may,must,could,might,shall ,should,will,would,ought to,need,dare一般这些开头的,都是情态动词的一般疑问句
(1)情态动词+动词完成式:must have done
(2)情态动词+动词进行式:must be doing
(3)情态动词+动词完成进行式:must have been doing
(4)某些情态动词的特殊用法:need
是 反问疑问句
can,may,must,could,might,shall ,should,will,would,ought to,need,dare一般这些开头的,都是情态动词的一般疑问句
(1)情态动词+动词完成式:must have done
(2)情态动词+动词进行式:must be doing
(3)情态动词+动词完成进行式:must have been doing
(4)某些情态动词的特殊用法:need