人不可貌相,海水不可斗量
有人译为：
A man can not be known by his look, nor can the ocean be measured by a dipper.
这样的译法只是直译,如果能够稍加修改,老外就能了
A man can not be judged by his appearance, nor can the water in the sea be measured by a bucket.
不过,老外通常的说法是这样的：
We can not judge a person by appearance only. 或 You can not judge a book by its cover.
(意思是：一本书的好坏取决于它的内容,而不是它的封面装帧的漂亮与否.)
参考：http://hi.baidu.com/%D1%D3%D0%C0/blog/item/2fc464cb3f91f31ebe09e683.html