____ wide spread of H1N1 is _____ challenge for the whole world. Confidence, cooperation and responsibility are keys to overcoming it.
________,I have to put it away and focus my attention on study this week.
—Smoking is bad for your health. —Yes, I know. But I simply can't________.
More than one student________he is________a teacher to them.
Grandpa used to tell us something about the “Cultural Revolution” ________he had time to spare.
—How nice it is meeting you here! —________,bye.