Passage Two
[29]Moods, say the experts, are feelings that are likely to be fixed, having effects on one's outlook for hours, days, weeks or even years. That's great if your mood is a pleasant one, but it will be a problem if you are sad, anxious, angry or simply lonely.
Perhaps the best way to deal with such moods is to talk them out; sometimes, though, there is no one to listen. Modern pharmacy offers a lot of anti-anxiety drugs. [30]What many people don't realize, however, is that scientists have discovered the effectiveness of several non-drug methods to make you free from an unwanted mood. These can be just as useful as drugs, and have the added benefit of being non-poisonous. So next time you feel out of sorts, don't head for the drug store-try the following method.
[30]Of all the mood-changing self-help techniques, aerobic exercise seems to be the best cure for a bad mood. "If you could keep the exercise, you'd be in high spirits," says Kathryn Lance, author of Running for Health and Beauty. Researchers have explained biochemical and various other changes that make exercise seem preferable to drugs as a mood-raiser. Physical work such as housework, however, does little. [31]The key is aerobic exercise-running, cycling, walking, swimming, or other repetitive activities that increase the heart rate and circulation, and improve the consumption of oxygen. You may do them for at least 20 minutes a time, three to five times a week.

Questions 29 to 31 are based on the passage you just heard.
29. What is the effect of moods on people?
正确答案：A
解析：细节题。“专家们认为情绪有可能是稳定的，会影响人生观长达几小时、几天、几周甚至几年”，故A为答案。
30. What is the best way that most people don't realize to keep a good mood?
正确答案：C
解析：细节题。短文提到，很多人没有意识到，科学家们已经发现有几种非药物的方法可以有效地让人们远离焦虑；然后提出其中最好的方法就是aerobic exercise，故C为答案。本题也可以通过排除法解题；A、D为多数人已知的方法；B未提及。
31. According to the speaker, why is aerobic exercise able to cheer people up?
正确答案：D
解析：细节题。短文末尾提到有氧运动提高心率、加快血液循环和改善耗氧量，故答案为D。