21. Their plan was _____. With it we had little trouble in finishing the work.
A. success B. succeed C. a success D. a successful
22. To our surprise, we got _____ people to attend the meeting as we expected.
A. as twice B. twice many C. twice many as D. twice as many
23. The boss has given everyone a special holiday, so we _____ go to work tomorrow.
A. can’t B. mustn’t C. needn’t D. shouldn’t
