A．/；the B．the；/ C．an；the D．the；a

答案　A　[air pollution是抽象名词，这里是泛指，weather这里是特指全球的气候，即the weather around the world。]

15．-What happened to you?

-I ________in the street when someone patted me on the shoulder，which frightened me.

A．was walking

B．had walked

C．was about to walk

D．was on the point of walking

答案　A　[此处意为：我正在街上走着，这时有人拍我的肩膀，吓了我一跳。be doing...when...正在做......这时......，符合语境。]

Ⅱ.阅读理解

In a world with limited land，water and other natural resources(资源)，the harm from the traditional business model is on the rise.Actually，the past decade has seen more and more forests disappearing and the globe becoming increasingly warm.People now realize that this unhealthy situation must be changed，and that we must be able to develop in sustainable(可持续的)ways.That means growth with low carbon or development of sustainable products.In other words，we should keep the earth healthy while using its supply of natural resources.

Today，sustainable development is a popular trend in many countries.According to a recent study，the global market for low­carbon energy will become three times bigger over the next decade.China，for example，has set its mind on leading that market，hoping to seize chances in the new round of the global energy resvolution.It is now trying hard to make full use of wind and solar energy，and is spending a huge amount of money making electric cars and high­speed trains.In addition，we are also seeing great growth in the global markets for sustainable products such as palm oil(棕榈油)，which is produced without cutting down valuable rainforest.In recent years the markets for sustainable products have grown by more than 50%.

Governments can fully develop the potential of these new markets.First，they can set high targets for reducing carbon emissions(排放)and targets for saving and reusing energy.Besides，stronger arrangement of public resources like forests can also help to speed up the development.Finally，governments can avoid the huge public expenses that are taking us in the wrong direction，and redirecting some of those expenses can accelerate the change from the traditional model to a sustainable one.

The major challenge of this century is to find ways to meet the needs of a growing population within the limits of this single planet.That is no small task，but it offers abundant new chances for