He entertained us to dinner last night.

求教这个 to dinner 的成分，我个人感觉是状语，entertain 的状语。

(1)entertain sb with sth

(2)entertain sb to sth

（to dinner是状语成分）

翻译大概是：他昨晚设宴款待我们。

My reply to your question is as follows:

Your understanding upon the above sentence is right!

entertain  vt.招待;款待 

(英文解释：If you entertain people, you provide food and drink for them, for example when you have invited them to your house.)

 I don't like to entertain guests anymore. 

我再也不想招待客人了。

You weren't allowed to entertain men in your rooms even with a chaperone. 

即使你有监护人陪同，也不允许在房间里招待男性。

    He 是主语，entertained是谓语，us是宾语， to dinner 是宾语补足语，last night是时间状语。