倍数+比较级+than表示的是多几倍。
He is two years younger than you. 他比你小两岁。
The new building is twice higher than the old one. 这座新楼是旧楼的三倍高。
=The new building is three times the height of the old one. 这座新楼是旧楼的三倍高。
=The new building is three times as high as the old one. 这座新楼是旧楼的三倍高。