Part B 二选一题(20分) 选题一

　　AIDS

　　AIDS is a life-threatening sickness that arracks the body’s natural defense system against disease. It can destroy the body’s ability to protect itself.

　　AIDS itself does not kill. But because the body’s defense system is damaged, the patient has little ability to fight off many other diseases, such as pneumonia, cancer, blindness and mental disorders.

　　The AIDS virus is carried in a person’s body fluids. The virus can be passed sexually or by sharing instruments used to take intravenous drugs. It also can be passed in blood products or from a pregnant woman with AIDS to her developing baby.

　　Many stories about the spread of AIDS are false. You cannot get AIDS by working or attending school with someone who has the disease. You cannot get it by touching drinking glasses or other objects used by such persons. Experts say no one has gotten AIDS by living with, caring for or touching an AIDS patient.

　　选题二

　　MYSTERY OF TIME

　　If you can read a clock, you can know the time of day. But no one knows what time itself is. We cannot see it. We cannot touch it. We cannot hear it. We know it only by the way we mark its passing. For all our success in measuring the tiniest parts of time, time remains one of the great mysteries of the universe.

　　One way of thinking about time is to imagine a world without time. Then there could be no movement, because time and movement cannot be separated. A world without time could exist only as long as there were no changes. For time and change are linked. When something changes, you know time has passed. In the real world, changes never stop. Some changes happen only once in a while, like an eclipse of the moon. Others happen repeatedly, like the rising and setting of the sun. People have always noted natural events that repeat themselves. When people began to count such events, they began to measure time.