Where is Jack?I can't find him anywhere.he___his homework upstair_英语解答

Where is Jack?I can't find him anywhere.
he___his homework upstairs.
A must have done B must be doing
我知道这里应该选择must be doing 理解为他正在楼上做作业.可是为什么不能选择must have done呢?这里不是问JACK在哪里吗?那应该表猜i测阿.must have done 不就是表猜测的嘛.如果不是的话,在哪种情况下用must have done 比较合适?

人气：242 ℃　时间：2020-06-03 04:24:30

解答

我来解释一下,
have done 是完成时态.mus thave done 指一定已经完成了,与语境不符.
如果不懂欢迎提问.