In my opinion,life in the twenty-first century is much easier than ________.
A.that used to be B.it is used to C.it was used to D.it used to be
D 为什么不选A
为什么上题用it
The weather in Beijing is colder than that in Hunan.这个就用 that?
并且,下面句子是否正确
life in the 21 century is much eaiser than that in the past