21. —Is Jack on duty today?
     —It_____ be him. It's his turn tomorrow.

A. mustn't    B. won't     C. can't D. needn't

22. There is a(n) ________ of 200 yuan for the person who returns the lost necklace to its owner.

A. reward      B. prize      C. award      D. Praise

23. It's surely a surprise ______ the event is successful.
     A. that     B. what       C. whether      D. when

24. There's a man at the reception desk who seems angry. I think he means ________ trouble.

A. causing      B. to cause      C. to have caused    D. having caused

25. —What was she doing when you came in?
    —She was ___ the view from the window.

A. respecting    B. admiring      C. gathering D. hunting

26. On October 1st everyone in China holds fun activities _______ the birthday of the People's Republic of China.

A. celebrating    B. memorizing      C. favoring    D. announcing