选b
用times表示倍数的时候有以下几种情况
1.be+倍数+as+计量形容词原型+as
如this tree is three times as tall as that one
2.be+倍数+计量形容词比较级+than
this tree is three times taller than that one
3.be+倍数+the+计量名词+of
this tree is three times the height of that one
4 倍数+as many/much+名词+as
he has got three times as many books as his siste