76. "Substance abuse" (Line 5, Paragraph 1) is preferable to "drug abuse" in that ____.

1. substances can alter our bodily or mental functioning if illegally used
2. "drug abuse" is only related to a limited number of drug takers
3. alcohol and tobacco are as fatal as heroin and cocaine
4. many substances other than heroin or cocaine can also be poisonous

77. The word "pervasive" (Line 1, Paragraph 2) might mean ____.

1. widespread
2. overwhelming
3. piercing
4. fashionable

78. Physical dependence on certain substances results from ____.

1. uncontrolled consumption of them over long periods of time
2. exclusive use of them for social purposes
3. quantitative application of them to the treatment of diseases
4. careless employment of them for unpleasant symptoms

79. From the last paragraph we can infer that ____.

1. stimulants function positively on the mind
2. hallucinogens are in themselves harmful to health
3. depressants are the worst type of psychoactive substances
4. the three types of psychoactive substances are commonly used in groups

80. Which of the following might be the main idea of the text?

1. "Drag abuse" has been replaced by "substance abuse".
2. Substances dependence is a common phenomenon.
3. Substances taken in excess will damage physical health.
4. Measures should be adopted to stop substances abuse.

(Reference keys.)