The World Health Organization says as many as 10 million persons worldwide may have the virus (病毒) that causes AIDS. Experts believe about 350 thousand persons have the disease. And one million more may get it in the next five years. In the United States, about 50,000 persons have died with AIDS. The country’s top medical official says more than 90 percent of all Americans who had the AIDS virus five years ago have been dead.
There is no cure for AIDS and no vaccine (疫苗) medicine to prevent it. however, researchers know much more about AIDS than they did just a few years ago. We now know that AIDS is caused by a virus. The virus invades healthy cells including white blood cells that are part of our defense system against disease. It takes control of the healthy cell’s genetic (遗传的)material and forces the cell to make a copy of the virus. The cell then dies. And the viral particles move on to invade and kill more healthy cells.
The AIDS virus is carried
A. An AIDS mother can pass on the virus to her unborn child.
B. The AIDS virus can be passed on through infected blood.
C. The AIDS virus can be passed on by shaking hands and sharing belongings.
D. The AIDS virus is passed sexually.
You are familiar with Prof. Peter, an expert in translation. Last night your colleague, Li Fang asked you to recommend him to Prof. Peter and wanted to be his assistant. Now you are asked to write a letter of recommendation.
Write your letter with no less than 100 words; write it neatly on ANSWER SHEET 2. Do not sign your own name at the end of letter; use "Li Ming "instead. You don’ t need to write the address. ( 10 points)
Expanded use of computer technology, development of stronger and lighter materials, and research on pollution control will produce better, "smarter" automobiles. In the 1980s the notion that a car would
"talk" to its driver was science fiction; by the 1990s it had become reality.
Onboard navigation was one of the new automotive technologies in the 1990s. By using the satellite-aided global positioning system (GPS), a computer in the automobile can pinpoint the vehicle’s location within a few feet. The onboard navigation system uses an electronic compass, digitized maps, and a display screen showing where the vehicle is relative to the destination the driver wants to reach. After being told the destination, the computer locates it and directs the driver to it, offering alternative routes if needed.
Some cars now come equipped with GPS locator beacons, enabling a GPS system operator to locate the vehicle, map its location and, if ne
A. it can locate the vehicle within a few feet
B. it can show where the vehicle is relative to the destination the driver wants to reach
C. after being told the destination, the computer locates it and directs the driver to it
D. after being told the destination, the computer can offer the driver alternative routes if needed
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