[单项选择]For some people, it may be better
A. to wear a seat belt for health reasons.
B. not to wear a seat belt for health reasons.
C. to get a valid medical certificate before wearing a seat belt.
D. to pay a fine rather than wear a seat belt.

[单项选择]For some people, it may be better ______.
A. to wear a seat belt for health reasons
B. not to wear a seat belt for health reasons
C. to get a valid medical certificate before wearing a seat belt
D. to pay a fine rather than wear a seat belt

[单项选择]Some people fear thatair pollution may bring about changes inweather around the world.
A. / ; the
B. the; /
C. an; the
D. the; a

[单项选择]Why do some people think hemp is better than trees for paper industry
A. It is cheaper to grow hemp than to cut down trees.
B. More paper can be produced from the same area of land.
C. Hemp planting can beautify the environment.
D. Hemp can produce paper of high quality.

[单项选择]Young people may grow quickly in some ways and more slowly in ______.
A. the other
B. some other
C. others
D. these others

[单项选择]People with ethnocentrism may enjoy eating something unacceptable in their culture if ______.
A. they are ignorant what is served
B. they do not have a biased attitude
C. it is well cooked and tastes delicious
D. it adheres to their ethnic preferences

[单项选择]

Smoking, which may be a pleasure for some people, is a serious source of discomfort for their fellows. (21) ,medical authorities express their concern about the effect of smoking (22) the health not only of those who smoke but also of those who do not. In fact, non-smokers who must involuntarily inhale (吸入) the air (23) by tobacco smoke may suffer more than the smokers (24) ．
Smoking is prohibited in the theatres and in the halls used for showing films (25) in laboratories (26) there may be a fire hazard (危险). Elsewhere, it is up to your good (27) ．
I am (28) asking you to maintain "No-Smoking" in classrooms and seminar rooms. This will prove that you have the (29) health in mind, which is very important to a large (30) of our students.

21（）
A. feeling
B. sense
C. realize
D. think