This box is heavier than that one.(同义句转化）

This box is heavier than that one.
=That box is lighter than this one.
=That book isn't as heavy as this one.
=That book is less heavy than this one.

That box is lighter than this one.

that box is lighter than this one.

This box is heavier than that one.
This box is not as heavy as that one./That box is lighter than this one./This box is less heavy than that one.
答案放心用，我是从事英语的，乐意为你解答。