must be . must have been.may be .may have been.如果
发布网友
发布时间：2024-10-23 21:42
共2个回答
热心网友
时间：2024-10-26 13:28
must be + doing/done
must have been +done
may be +doing/done
may have been+ done
热心网友
时间：2024-10-26 13:29
动词在be been后面加ing是代表progressive 也就是进行时态 也可以加动词的过去分词 代表passive voice 也就是被动语态
