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. Text messages can be a good way to spread information, particularly to groups who are hard to reach by _______ means, such as teenagers.
A. another B. other C. the other D. others