Is there           in this story.

(2013·新课标全国卷Ⅱ)It's an either­or situation —we can buy a new car this year or we can go on holiday but we can't do ________.

How wonderful it will be that whoever is in need of a job can get        ．

We feel _____ our duty to make our country a better place.

 --- How many of you have solved the math problem?--- ________, the math problem is far too difficult for us to work out. .