阅读下面的短文，并根据短文后的要求答题。(请注意问题后的词数要求)
［1］Every year, lots of children die in traffic accidents, and many of these tragedies occur because child safety seats are not properly installed or are not used at all. As more and more families buy private cars, it’s time to _______________ the safety of children.
［2］Parents tend to let the child sit alone in the front passenger seat, or leave the child alone in the back of the car without any safety restraints, have the child held in an adult’s lap, or have the child use an adult’s safety belt. All of these can potentially add elements of danger for a child in a car.
［3］In the 1970s, Western countries began to research safety devices for children in cars. It was later found that special safety devices for children in cars will help to reduce injury by about 70 percent, and child safety seats play a key role in protecting children in case of traffic accidents.
［4］Since 1999, automakers have been required to put child restraint systems in cars in the United States. There are more than 25 million child safety seats in the United States, compared to only 600,000 in China. Today, more than 40 countries in the world have already issued relevant legal regulations, making it compulsory that children sit in safety seats. In Germany, the Netherlands and Japan, children under 12 years old are required to sit in child safety seats.
［5］China is a manufacturing base for child safety seats, but the market in China is still limited. As a result, while we export our products to other countries, our own children in China are rarely provided with safety seats for various reasons. We hope this situation will be improved.
小题1:What’s the main idea of Paragraph 2?(no more than 10 words)
小题2:Fill in the blank in Paragraph 1 with proper words. (no more than 5 words)
小题3:Explain the underlined sentence in Paragraph 5?
小题4:List at least 3 elements of danger for a child in a car.
1）
2）
3）
小题5:What does the author want to tell us by writing such an article? (no more than 12 words )
为规范型，并写出所做的可逆线性变换．