21. — We have missed the train! — _____, there’ll be another in ten minutes.
A. That’s fine B. Never mind C. Come on D. Don’t mention it
22. —Now that you like the portable personal computer so much? Why not buy one?
—Well! I can’t afford _____ computer at present.
A. that expensive a B. a such cheap C. that an expensive D. so a cheap
23. The boy wanted to ride his bicycle in the street, but his mother told him _____.
A. not to do B. not to C. not do it D. do not to
