You 'd better do it yourself 的yourself前不加by吗?

问题描述:

You 'd better do it yourself 的yourself前不加by吗?

by加或不加都可以.
yourself 可以解释为 "你亲自,你本人", 表示强调,直接跟在you后面,不用加by, 例: You yourself know it. "你自己知道."
加by则成为状语短语by yourself, 意为"你单独地; 你独立地".