You---TV last night since there was a power--cut.A.mustn't h

B
昨晚你不可能看电视了,因为停电了.
对过去的推测,应该是“情态动词+have done sth.”,先排除CD.
对过去肯定的推测,用must have done sth.,如：
The ground is wet.It must have rained last night.
地面是湿的,昨晚肯定下雨了.
而否定的推测用can't have done sth.,表示“不会”,如题所示.