As far as I know 据我所知
1.As we all know,2.As is known to all正如大家所熟知的
1.I think 2.I'd like to say我认为
By contrast 相比之下,.
On the contrary于此相反
表示倍数的方法 A是B的几倍
1.A is twice(three times)+as+adj/adv+as+B
2.A is twice(three times)+adj/adv的比较级+than +B
3.A is twice(three times)+the+size/height/length/width/depth+of+B
A is much+adj的比较级+ than+twice(three times)+ of+B A比B的几倍还多