题目

A lot of people are crazy about doing shopping through the Internet now. Why is it so popular? There are some reasons. First, more and more people have their own computers and their computers can be joined with the Internet. So it is possible for many of them to do shopping through the Internet. Second, shopping through the Internet can save them some money and a lot of time. Third, they don’t need to go to the shop themselves. Because of these good facts, few people refuse it. On the other hand, some people don’t like this new way of shopping. They are worried about the safety of13．用递等式计算．（147-49）×12         2800-25×18         62+13×26318÷6+165         2300-54×19          15×（61-45）