II.单项填空(共15小题;每小题1分,满分15分) 21.---I’m afraid I must be off now . --- ____________________ .
When you introduce me to Mr. Johnson, could you please sayfor me?
—Is there any other studentwants to visit Wutai Mountain?
—The problem is very difficult. I'm afraid you can't work it out now.—I fail this time, I will try it again.
Richard looked at the envelope andJenny's handwriting immediately.
There's a big difference between saying you'll do something anddoing it.