题目

某城市按以下规定收取每月煤气费，用煤气不超过60立方米，按每立方米0.8元收费；如果超过60立方米，超过部分按每立方米1.2元收费．如甲用户某月份用煤气80每立方米，那么这个月甲用户应交煤气费用为60×0.8+（80﹣60）×1.2=72元． （1）设甲用户某月用煤气x立方米，用含x的代数式表示甲用户该月的煤气费． 若x≤60，则费用表示为_________ ；若x＞60，则费用表示为____________ ． （2）若甲用户10月份的煤气费是84元，求甲用户10月份用去煤气多少立方米？We all need a healthy environment, but we produce waste every day and it is harmful to our environment. Though we are young, we can still do something to help. In fact, even the simplest daily activities can make a real difference to the environment. Here are some ideas for you to live a green life. Remember these three words; reduce, reuse and recycle. Reduce means “use less”. Don't waste things. This saves money and reduces pollution and waste going into the environment. Before we buy something new, think if it is really necessary or maybe the old one will be just as good! If we buy things, choose local products if possible, and try not to buy too many things from abroad. Reuse means “use again”. Use things for as long as possible. When we buy things, make sure that they last a long time. We should take care of them so that they will last, and we should repair them if we can instead of throwing them away and buying new ones. Don't use a paper cup or a paper bag. It's better to use a glass and a lunch box because you can use them again. Recycle means “change things into other things”. Although it takes energy to change something into other things, it's better than throwing things away or burning them. Find out what can be recycled in your neighbourhood and take part in recycling programmes. We should also buy products made from recycled materials, such as recycled paper, to help save trees. Title:    1   to Live a Green Life We produce waste every day and it does  2    to us. We can do something to help. Ideas What to do What not to do To   3      Use less * Try to save something. * Don't buy too many things from foreign  4   . To reuse Use  5 * Use things for us as long as possible. * Buy things that last long. * Look  6  things or repair the old things. * Don't use  7   cups or bags. To recycle Change things into something  8  . * Join in recycling programmes. * Buy products made9  recycled materials. * Don't  10  things away or burn them.