500　oblige，be obliged to和be obliged to do

① oblige意为“迫使，责成”，为及物动词，结构为：

oblige sb. to do sth.

be obliged to do sth.

They obliged him to leave the house. 他们迫使他离开了那所房子。

He was obliged to work for the boss without any pay. 他被迫为老板干活，没有任何报酬。

② be obliged to sb. for sth./doing sth.意为“为……而感谢/恩”。这时obliged可用much，very much修饰。

He's much obliged to you for all you've done for him. 他十分感谢你为他做的一切。