must have been是对过去正在进行的事肯定？还是对过去的事进行肯定？？

Question

如题所述

Answer 1

使用 must have v+ed 这个句型是表达对已经发生的事情作出的肯定判断。例：
John was surprised to see the white coating on the roof and said to himself: "It must have snowed last night." 约翰吃惊地发现房顶裹上了一层白色，自言自语地说“昨晚一定下过雪了。”

同理，must have been v+ing 表达对过去某一段时间里持续发生的动作一个肯定的判断。例：
He must have been sleeping when the earthquake hit his village.
"God must have been sleeping": faith as an obstacle and a resource for Rwandan genocide survivors in the United States.

Answer 2

对已经发生的事实的肯定。至于是不是正在进行，要看been后面的动词形式。

Answer 3

现在，因为have是原形，如果是had就是过去了