全国英语六级考试模拟试卷（六）

Passage Two

You might think that most of the patients at sleep clinics are being treated for sleeplessness, commonly referred to as insomnia, but that is not the case. The majority of sleep-clinic patients suffer from disorders of excessive sleep or ¡°hypersomnia¡±. While most insomniacs somehow manage to drag themselves through the day and function at acceptable, although not optimal, levels. This is not so for people who suffer from hypersomnia.
They are incapacitated by irresistible urges to sleep during the day, often in inappropriate situations-at business meetings, in supermarkets, or at parties. Even more dangerous is their failure to remain awake when driving or operating machines. Falling asleep in such situations could obviously be life-threatening.
Many hypersomnia suffer from narcolepsy, for which the primary symptom is excessive daytime sleepiness. Though not apparent in childhood, this symptom most often appears for the first time during the teen years and continues through a person's life. The sleep attacks may occur as many as fifteen to twenty times during the courses of the day and last for periods from fifteen minutes up to two hours.
What can be done to help those suffering from narcolepsy? There are certain drugs that can help, and specialists suggest voluntary napping to decrease the frequency of such sleep attacks.

14. What does the speaker say about sleepª²clinic patients?
15. When does narcolepsy usually first become apparent?
16. What can a narcoleptic do to prevent sleep attacks?

Passage Three

Words came from California of a new weapon in the war on household pests. Two scientists working for a firm in Anahelm, California, have developed a method to eliminate insects without using dangerous chemicals. The new poison? Hot air.
The basic idea is that insects cannot adjust to temperature much above normal. In laboratory experiments, cockroaches and termites can't survive much more than a quarter of an hour at 125 degrees Fahrenheit, or about 50 degrees centigrade.
The new method involves covering a house with a huge tent and filling it with air heated to around 65 degrees centigrade. Hot air is forced in with fans, and the tent keeps the heat inside the house. Since termites try to escape by hiding in wooden beams, the heat treatment must be continued to a full six hours. But when it's all over, and the insects are dead, there are no toxic residues to endanger humans or pets.
Scientists claim that there is no danger of fire, either, since very few household materials will burn at 65 degrees centigrade. In fact, wood is prepared for construction use by drying it in ovens at 80 degrees centigrade, which is substantially hotter than the air used in this procedure.

17. What is the talk mainly about?
18. What makes the new system better than other treatments?
19. Why are the houses covered with tents?
20. Why does the speaker mention that construction wood is dried by heat?