单选题 Questions 15 through 18 are based on the following passage.
【正确答案】 A
【答案解析】[听力原文]
Research shows that whether a person is an optimist or apessimist is related to their quality of life, including their physical health. The subjects involved first took personality tests in the 1960"s and then thirty years later they completed a follow-up self-assessment of their health status. Researchers found that not only did the optimists from the 1960"s report better physical and mental functioning thirty years later, but that optimists also lived longer on average than pessimists. It"s hardly clear that there is a causal relationship between optimism and health. It could be that they are related to the same underlying gene complex or set of mechanisms. Still, it sure is tempting to surmise that it"s partly a positive attitude that keeps people alive for so long. It may actually be possible that a lot of what my parents have been telling me for years is true. If you think positively, good things may happen to you. If you think negatively, then you may doom yourself.

What is related to one"s personality?
【正确答案】 C
【答案解析】[听力原文]
When was the first personality tests made?
【正确答案】 B
【答案解析】[听力原文]
What"s the personality tests found according to the passage?
【正确答案】 B
【答案解析】[听力原文]
What"s the author"s opinion according to the passage?