已知直线l过点（2，1），且在两坐标轴上的截距互为相反数，则直线l的方程为（ ）

经过点P（1，2）且与直线x-y+2=0平行的直线的方程是______．

背一背，填一填。

       春天来了！我们                               ，我们                              ，我们                                    ，我们触到了她。她在柳枝上荡                    ，在风筝尾巴上                          ；她在喜鹊、杜鹃嘴里                           ，在            、              枝头笑……

A

Napoga is a 12-year-old girl in Ghana(加纳), Africa. It is hard for her family to get clean water. Every morning, she leaves home at half past five to get clean water for her family in a village far away. It takes her six hours to get enough clean water for daily (日常的) cooking and drinking. She has no time to go to school or to play with her friends. Millions of people in the world are like Napoga. They can’t get enough clean water to keep healthy.
Earth Day is April 22. But on all other days, we must also remember it. The water we use is the most important natural resource(自然资源) on the earth.
Water covers 70% of the earth’s surface(表面). But most of that is sea water. We can’t use it for very many things. Fresh water covers only 1% of the earth’s surface.
You probably feel lucky that your life isn’t as hard as Napoga’s. But that doesn’t mean you don’t have to worry about water. We all face serious water problems. One of them is water pollution. All kinds of things from cars, factories, farms and homes make our rivers, lakes, and oceans dirty. Polluted water is very bad for people to drink. And dirty water is bad for fish, too. Now, 34% of all kinds of fish are dying out.
How do cars and factories make our water dirty First, they pollute the air. Then, when it rains, the rain water comes down and makes our drinking water dirty. Dirty rain, called acid rain (酸雨), is also bad for plants, animals and buildings.
Scientists say that in 30 years, more than half of the people in the world won’t have enough clean water. We have to learn how to save more water for ourselves and our children. Here is some advice for saving water:
Turn off the water while you brush your teeth. You can save as much as 450 liters (升) each month.
Leaky taps(水的龙头) waste a lot of water. Fix them right away!
You can easily cut your 1O-minute showers(沐浴) in half—and you’ll be just as clean.
When you wash dishes, don’t let the water run.
Only wash clothes when you have a lot to wash. If your washing machine isn’t full, you’re wasting water!

What’s the main idea of the passage ( )

A．Something must be done to prevent water form being polluted.

B．Clean water means much to human beings and living things around us.

C．It’s time to take care of the water we use.

D．Water is the most important natural resource on the eart

气管异物容易发生的部位（）。

A.气管

B.左主支气管

C.右主支气管

D.中间支气管

某公司有一完整工业投资项目，设备投资15400元，开办费500元，垫支流动资金1000元。该项目建设期为一年，发生建设期资本化利息100元，设备和开办费投资于建设起点投入，开办费于投产当年一次摊销完毕，流动资金于设备投产日垫支。该设备寿命为3年，按直线法提取折旧，预计净残值500元。预计投产后每年销售收入增加额分别为 10000元、20000元、15000元，每年经营成本增加额分别为4000元、12000元、5000元，经营期每年利息支出110元。企业所得税率为40%。
已知：(P/F，8%，1)=0.926
(P/F，8%，2)=0.857
(P/F，8%，3)=0.794
(P/F，8%，4)=0.731
要求计算：
(1) 设备年折旧。
(2) 投产后的各年净利润。
(3) 计算期各年净现金流量。
(4) 项目投资的净现值。
(5) 项目的投资利润率(按净利润)。