Isn't it time you got down to __________ the papers?
Mobile phone users have developed a series of symbols, such as and to show ________ they feel.
Inside the White House, there is a room called the Oval Office. That's ________ President Obama works.
________ I regret most is that I have promised to make friends with the dishonest girl.
We can find out ________ all the excitement is about by playing QQ's “Happy Farm”.
I can't figure out ________ it is that makes him so difficult at school.