that's easy,Bob is twice as old as jack,so he is now thirty.中的as old as
问题描述：
that's easy,Bob is twice as old as jack,so he is now thirty.中的as old as
答
as old as 和...年龄一样大
twice as old as 年龄是..两倍
bob是jack年龄两个倍,所以他现在30岁了.