Question

must be和must have be有什么区别

Answer 1

　　must be和must have be的区别主要是：must have been表示对过去情况作推测；must be表示所对现在情况的推测。例如：
　　1、He must be ill.
　　他一定是病了。（指现在有病）
　　2、He must have been ill.
　　他当时一定是有病 / 他一定生过病。（指过去有病）
　　3、He must be very rich.
　　他一定非常富有。（指现在有钱）
　　4、He must have been very rich.
　　他当时一定非常富有 / 他一定曾经富有过。（指过去富有过）

Answer 2

简单地说：对过去情况作推测,用must have been；所对现在情况作推测,用must be.
比较：
He must be ill. 他一定是病了.（指现在有病）
He must have been ill. 他当时一定是有病 / 他一定生过病.（指过去有病）
He must be very rich. 他一定非常富有.（指现在有钱）
He must have been very rich. 他当时一定非常富有 / 他一定曾经富有过.（指过去富有过）
下面是几个must have been的例子,有一定的背景或语境,你可以体会一下：
She must have been very young when she got married. 她结婚时一定很年轻.
I didn't hear the phone. I must have been asleep. 我没有听到电话铃,我一定是睡着了.
When you got lost in the forest you must have been very frightened. 当你在森林里迷路的时候,你一定很害怕吧.
I must have been blind not to realize the danger we were in. 我一定是瞎了眼,连我们身临险境也看不出来.
这下你明白must be与must have been 的区别了吗?该不会再误用must have been与must be了吧!

希望能帮到你！

Answer 3

是must be和must have done
must be是必须做某事，must have done说法是错误的,只有can have done过去可能做某事

Answer 4

第二个应该是 must have been

追答

那是过去式

比如 You look so tired, you must have stayed up late. 过去时

还有

You must be John, Amy told me all about you.

你肯定就是约翰了，艾米告诉我关于你的很多事