题目

已知:P={xx2-8x-200},S={xx-1m}     ①是否存在实数m,使得xp是xs的充要条件?若存在,求m 的取值范围 ②是否存在实数m,使得xp是xs的必要条件?若存在,求m的取值范围 答案:答案 若是的必要条件则S  P     1-m-2    m3   存在m3使得是的                                    必要条件         1+m10阅读下面材料,从每题所给的三个选项(A、B和C)中,选出最佳选项。Japan is one of the cleanest countries in the world. What are its secrets?In Japan, people have to pay for their garbage. If they have a lot, or their garbage is difficult to treat, they have to pay more. They also have to pay for things they no longer need, like old TVs and fridges. This makes people think before they throw away.There are few garbage cans in Japanese streets. People take their garbage home and sort through it carefully. They also have different ways of treating different kinds of garbage. People turn old chopsticks into paper. They burn some garbage to make fertilizer(肥料). People even use garbage to make more land area.Japan has set a good example to the rest of the world. If people in every country did the same, we would be able to do something about our environmental problem.What can we do to help the environment? Here are some ideas.Reduce!Check it out. Buy products with less packaging (包装).Buy less and create less garbage. We shouldn’t buy things we don’t need.Reuse!Be creative and make use of garbage. For example, you can make a photo frame(边框) out of buttons, and other small pieces of garbage.Recycle!Ask your family and friends to use recycled products.Be helpful. Is there a recycling center near your home? If so, ask your family and neighbors to recycle.【1】What does the underlined word “treat” probably mean in Chinese?A. 治疗 B. 丢弃 C. 处理【2】Paragraphs(段落) 1- 4 of the passage mainly tell s about _______.A. the secrets of Japan’s being a clean countryB. what we should do to help the environmentC. different kinds of ways to make use of garbage【3】How many ideas does the passage mention about helping the environment?A. Two. B. Three. C. Four.【4】What can we do to help the environment?A. Throw away all the garbage.B. Go shopping more often and buy things we don’t need.C. Ask our family and friends to use recycled products.【5】Which of the following is TRUE according to the passage?A. People in Japan should pay for their garbage.B. There are many garbage cans in Japanese streets.C. We can recycle the garbage by burning all the buttons.
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