When throwing away rubbish, do you know which bin(垃圾箱) it should go in? Have you ever noticed the differently-colored bins on the street?

Some of you might not be able to answer this question.【小题1】Knowing how to sort（分类）waste can make it easier to save energy and protect the environment.

If you don’t sort your waste, all of it will go to a landfill（垃圾填埋场）and be buried（埋）together.【小题2】 But some waste, like the metal part of a pen, can be used to make other things if they are properly recycled.

【小题3】 For example, Shanghai announced that within three years, people should sort their waste into four groups: wet, recyclable, harmful and dry.

【小题4】 Paper, metal, glass and other things that can be reused are recyclable waste. Harmful waste includes things like medicine and batteries.【小题5】

Now that you know this, perhaps you can do your part to protect the environment and encourage others to sort their waste.

Do you know the Air Quality Index（空气质量指标） or AQI report in the newspaper? The AQI helps us understand what the air quality around us means to our health. The AQI uses colours, numbers and words to tell us about the air. What do these colours and numbers mean? Let’s have a look.

When the AQI colour is green, just enjoy the clean air!Yellow shows the air quality is fine for most people. Orange tells us people with lung disease（肺病） should spend less time outdoors. When the AQI colour is red, people with lung disease and active kids and adults shouldn’t spend too much time outdoors. Everybody else should try to spend less time outside. Purple shows everybody should try not to go outside.

Hundreds of years ago, life was harder than it is today. People didn’t have modern machines.

Life today has brought new problems. One of the biggest problems is pollution. Water pollution has made our rivers and lakes dirty. It kills our fish and pollutes our drinking water. Noise pollution makes us talk louder and become angry more easily. Air pollution is the most serious kind of pollution to all living things in the world.

Cars, planes and factories all pollute our air every day. Sometimes the polluted air is so thick that it is like a quilt (被状物) over a city. This kind of quilt is called smog.

Many countries are making rules to fight against pollution. Factories must now clean their water before it is thrown away, and they mustn’t let dirty smoke go into the air.

We need to do many other things. We can put waste things in the dustbin and do not throw them on the ground. We can go to work by bus with our friends in the same car. If there are fewer people driving, there will be less pollution.

Rules are not enough. Every person must help to fight against pollution.