对于【duìyú】

对于 names what an opinion, a feeling or a way of dealing with something is aimed at. The 对于 phrase goes at the start of the sentence or straight after the subject, and the verb or adjective that comes later says what the attitude is.

It's more formal than 对, and it suits a reaction to an idea, a decision, a piece of work: 满意, 重视, 有意见, 不了解.

对于 or 对

Wherever 对于 works, 对 works too. The reverse doesn't hold. 对 also means "facing, to" a person – speaking to them, smiling at them, being kind to them – and 对于 has none of that.

• × 他对于我说 → 他对我说
• × 老师对于我们很好 → 老师对我们很好

对于 or 关于

关于 names a subject – what a book or a talk is about. 对于 names the target of an attitude. A title or a heading can be 关于 + noun on its own; it can't be 对于 + noun.

• × 我看了一本对于环境的书 → 我看了一本关于环境的书

对于 also opens 对于…来说, "for someone"; see 对…来说.