Passage Two Questions 26 to 30 are based on the following passage. We all know that humans are damaging the environment, but what can we do about it? Some people are trying to do their bit to be more environmentally friendly. Local councils in Britain encourage certain aspects of green living, such as recycling paper, tin, plastic and glass. They want to reduce the amount of rubbish going into landfill sites（填埋场），because they are running out of places to dump（倾倒）rubbish. In some areas rubbish for recycling is collected from your doorstep, but in other areas, you have to take it to a special recycling place, such as a bottle bank. Another way of reducing the amount of rubbish you create is to use reusable products instead of disposable ones For example, some people use strong shopping bags or boxes for their groceries instead of plastic carrier bags, or use washable nappies instead of disposables. More people are becoming interested in reducing their carbon footprint—the amount of carbon they use up. They try to reduce their carbon emissions（释放）by cycling, using public transport or an electric car, rather than driving gas-consuming vehicles. Some people choose not to fly for holiday trips because planes are the biggest producers of carbon emissions. You can make‘green’ choices when buying food too. It's best to buy food which was locally grown or produced so that it hasn't been imported by air, or shipped by road from far away. Houses can be environmentally friendly too. It takes less energy to heat a house if it has good insulation（绝缘，隔热）and double glazing (双层玻璃）．You can also create your own energy it you have solar panels or a wind turbine fitted though these can be expensive. You can also save water by using a rain water container for washing the car or watering the garden. It's even possible to use a system where‘grey water’—water which has been through a tap（水龙头）once already, is used to flush（冲洗）toilets. Some new housing projects are being built specifically to be as environmentally friendly as possible. 26．The purpose of collecting reusable wastes is to＿．