21. There is a saying, yesterday is history, tomorrow is a mystery ．But today is _____gift. That is why it's called ______ present ．
A．\ ; \ B． the; a C． \; a D． a ; the
22. — Did you enjoy the film you saw last night?
—______. I just did it for a change, as I was tired from working all day.
A. Not necessarily B. Not exactly C. Not really D. Not likely
23. It is reported that China will not buy the Euro debt until some thorough research ______.
A. has been done B. had been done C. will be done D. will have been done
