How can the government _______ the wishes of its people?

Children’s brains cannot develop properly _________ they lack protein.

Mr.Stevenson is great to work for ——I really couldn’t ask for a ________ boss.( 2011·全国Ⅱ)

Is this key ________–No, it isn’t. It’s ___________.

Living or studying abroad, you are supposed to 　　　　yourself to new manners and customs.