[单项选择]Complex as it may appear, the rocket, which was invented in China over 800 years ago, is a relatively simple device.
A. 火箭是800多年前在中国发明的，虽然看起来很复杂，其实是一个相对简单的装置。
B. 火箭是800多年前在中国发明的，虽然看起来很先进，但是一个简单的装置。
C. 火箭是800多年前在中国发明的，不管看起来有多复杂，肯定是—个相对简单的装置。
D. 火箭是800多年前在中国发明的，看起来并不先进，是一个绝对简单的装置。

[单项选择]Which one of the following may appear on a periapical radiograph of the upper third molar area
A. external oblique ridge
B. mylohyoid ridge
C. coronoid process
D. condyle

[单项选择]A passion for the theatre which may demonstrate all the ways of life can be a fairly satisfying ________ for life.
A. substance
B. imitation
C. repetition
D. substitute

[单项选择]The economic forces which may affect the new public offering of stock include sudden downturns in the market, hedging and other investor strategies for preventing losses, ______ the interest rates in Washington, and ______ undercapitalized.
A. loosing ... fearing the company may still be
B. loosening ... a fear of the company still being
C. a loosening of ... fearing that the company may still be
D. a loosening of ... a fear that the company may still be

[单项选择]Which may NOT be a reason for higher cancer death rates among US blacks
A. Unequal access to medical care.
B. Greater probability of having other diseases.
C. Differences in the biology of the cancer.
D. Early diagnosis.

[单项选择]According to the passage, which may be the best title
A. Storing Used Nuclear Fuel
B. Dealing with Nuclear Waste
C. Renewable Nuclear Power
D. Environment and Resources

[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