阅读理解。
In many societies, there is often greater acceptance of light skin than dark skin. Light skin may be seen
as a mark of beauty, intelligence and success. These beliefs can lead to social pressure even within the same
racial or ethnic group, if some members are darker skinned than others.
The result is that skin lightening has become a common activity across Africa, Asia and other areas of
the world. More and more people with dark skin are using skin-lightening products, even if they may face
health risks.
They believe that having whiter skin will improve their lives. Many people think they will have a better
chance of getting a job or marrying into a better family. Or they want to look like what their society generally
considers beautiful.
Some beauty care products and soaps contain chemicals that make skin lighter. This process is also called
bleaching. But some of the chemicals are extremely dangerous. One of the chemicals has been linked to
kidney (肾) damage and some kinds of cancer. It also causes low birth weight in babies when mothers use it
during pregnancy.
At first, bleaching products make the skin color lighter. But after long-term use they can cause problems.
They can even make some skin darker. The chemicals in the products block and break down the natural
process that gives color to skin. The skin loses its natural barrier to protect against sunlight. Then the skin
can become thick and discolored. Usually the person will use more of the product in an effort to correct the
problem, but this only makes it worse.
Fatimata Ly treats skin conditions in the Senegalese capital, Dakar. Doctor Ly says skin bleaching has
become a problem throughout Senegal. She says the chemicals are now more dangerous because they are
stronger. Some cases have resulted in blackened fingernails, infections and permanent skin damage.
And these are not the only risks. Experts say some people who change their skin color suffer emotional
damage. They feel regret and sadness. They feel that instead of risking their health, they should have learned
to love and accept their skin color as it was.
1. Which of the following words can replace the underlined word "bleaching"? [ ]
A. whitening
B. changing
C. lighting
D. pleasing
2. Why has the skin lightening become a common activity all over the world?[ ]
A. There are many products that can make the dark skin light.
B. Many people with dark skin have no confidence.
C. Relatively speaking, light skin has more advantages over dark skin.
D. People with dark skin are forced by the pressure of their families.
3. According to the text the following are the risks using the bleaching products EXCEPT ______. [ ]
A. blackened fingernails
B. permanent skin damage
C. emotional damage
D. a waste of time and money
4. From the text we can conclude the writer's attitude toward using the bleaching products is
probably ______. [ ]
A. supportive
B. positive
C. doubtful
D. negative
，A*是A的伴随矩阵，则(A*)-1=______．