Einstein was famous _________ a scientist _________ his Theory of Relativity.
—I'm sorry I stepped outside for a smoke. I was very tired.—There is no________for this while you are on duty.
—Would you like to go to the dinner party on Saturday?—Thank you. I'd love to,________I'll be out of town at the weekend.
—Haven't you realized the use________the used paper?—Yes, already.
Being determined is a kind of quality and that's________it takes to do anything properly.
—What do you expect Mr. Zhang to succeed in?—________.