21. The mail was ___ tor two days because of the heavy snows. 　　 　　A. held out B. held up C. held back D. held off 　　 　　22. The plans put forward in the meeting shall be ____ to the letter. 　　 　　A. carried on B. carried out C. proved D. practised 　　 　　23. ---How did you find your sister in such a big and strange city? 　　 　　--- I____ her in the railway station when I was just going back home. 　　 　　A. came about B. came out C. came up D. came across 　　 　　24. After a successful operation, Ronaldo has begun to do some exercise to ____ strength. 　　 　　A. improve B. decrease C. increase D. raise 　　 　　25. If you are wotking even harder,you ____ to be promoted to be a manager soon. 　　 　　A. promise B. wish C. turn out D. prove 　　 　　26. I have visited a lot of countries and stayed in many different five-star hotels, but none of 　　 　　them ____ this one. 　　 　　A. matches B. beats C. compares D. contrast 　　 　　27. ---How much is your sweater ____?