Comparing 对 ("dui4") and 对于 ("dui4yu2")

“对”和“对于”都是介词，用来引入动作的对象或与动作相关的人或事物。但“对”的使用范围更广，可以表示对待、朝向、关系等，而“对于”更正式，主要用于指出动作所涉及的对象或话题。

"对" and "对于" are both prepositions used to introduce the object of an action or the person/thing related to the action. However, "对" has a wider usage, indicating treatment, direction, relation, etc., while "对于" is more formal and primarily used to indicate the object or topic involved.

“对”常用于口语和书面语，可以接名词、代词或动词短语；表示“对待”时，常与“态度”“看法”等搭配。而“对于”多用于书面语，后面一般接名词性成分，用来引出话题或对象，语气较正式。在某些情况下两者可互换，但有些固定搭配（如“对得起”“对……负责”）中只能用“对”。

"对" is commonly used in both spoken and written Chinese, and can be followed by nouns, pronouns, or verb phrases; when indicating 'treatment,' it often pairs with words like 'attitude' or 'opinion.' "对于" is more written-oriented, usually followed by a noun phrase to introduce a topic or object, with a formal tone. In some cases they are interchangeable, but certain fixed expressions (e.g., 'deserving,' 'responsible for') only allow "对."