three is _____than one.

书上的答案是对的啊
首先,three is three times than one.是说三是一的三倍.
其次,as much as是指差不多的意思,Three is three times as much as one就是说三和一的三倍差不多的意思.
再次,three is twice more than one,这句话是说三比一多两倍的意思.注意区别这句和第一句,里面的twice其实等于two times,后面是more than意思是比……多.
最后,我觉得也可以说three is three times as one.

Three is three times as much as "one" 3是1的3倍
three is twice more than "one 3比1大2
2句都没有错。第一句3和3倍的1是一样多的，所以用AS MUCH AS，第二句是比较级，所以用。。。MORE THAN