Life in twenty-first century is much easier than ___used to be .A.what B.that C.it 具体说明原因

问题描述:

Life in twenty-first century is much easier than ___used to be .A.what B.that C.it 具体说明原因

C.it原因呢?没缺什么啊,it指life本身it used to be在这里是一个修饰成份,也可以说是一个从句,修饰itwhat 呢?不是缺主语吗