[masaegu]

Originally Posted by NinjaCrab

I have a question regarding the difference between ために and に in ~てくれる/~てあげる sentences.

あげる = an action is performed for the second and third person(s), including strangers.
くれる = an action is performed for the speaker or someone closely related to the speaker.

In Genki II, it says in a footnote that "If the main verb does not have a place for the person, use ために. 掃除する is one such verb". けんさんが私のために部屋を掃除してくれました。

The sentence is grammatical but is not something a native speaker would say in a real life situation. We would phrase it:
けんさんが私の部屋を掃除してくれました。

However, In my grammar dictionary it says that you only use ために with intransitive verbs. They provide the following example:

みんなは私のために働いてくれた。

Not true. Both transitive and intransitive verbs can be used.

This confuses me since 掃除する acts as a transitive verb in the above example. Would it be wrong to say:

けんさんが私に部屋を掃除してくれました。?

Yes, it would. You can only use certain verbs after the 「ＳＯＭＥＯＮＥが私に」.　　 掃除する is not one of them.

Those verbs include 買う、作る、届ける、送る、貸す、教える、見せる、与 える、etc. There will not be many more.