A．have produced B．have been produced

　　C．are producing D．are being produced

　　3)Mr Black said it was so，______ he was mistaken.

　　A．therefore B．otherwise C．besides D．however

　　2．These chemicals in the food supply build up in people's bodies over time.

　　随着时间的推移，食物中的这些化学成分会在人体中堆积。

　　考点：build up逐渐增强；建立；开发

　　Many a large and big business has been built up from small ones.

　　很多大企业都是从小规模发展起来的。

　　Our country has built up her fine reputation in the world.

　　我们的国家在世界上已逐步赢得好的声誉。

　　He has built up a good business over the years.

　　几年来他生意做得很兴旺。

　　1)build up还可意为"积累，积聚""变得严重起来，(车辆)拥挤起来"。如：

　　The clouds are building up.云越聚越多。

　　When the Spring Festival is coming，traffic builds up along the roads.

　　当春节到来时，路上的车辆越来越多。

　　2)build up可用于被动结构。如：

　　The area has been built up since I began to live here.

　　自从我住在这儿以来，这个地区已经盖满了房子。

　　归纳：be built up在句中表示"____________"。

　　3)派生词：

　　building n. 楼房；建筑物

　　单项填空

　　1) I'm very glad to see that your vocabulary is gradually ______.

　　A．building up　　　 B．turning up C．coming up D．waking up

　　2)Practising Chinese kungfu can not only______ one's strength，but also develop one's character.

　　A．bring up B．take up C．build up D．pull up

　　完成句子

　　3)好的食物可以增强我们的体质。

　　Good food can ______ us ______.

　　4)为了建设我们的城市，我们应该尽最大的努力工作。

　　______ ______ ______ our city，we should do our best to work.

　　3．Many of these chemicals can lead to cancer or other illnesses.

　　很多化学成分能导致癌症或其他疾病。

　　考点：lead to导致；造成(后果)

　　What on earth has led to the road's being crowded?

　　到底是什么导致了这条公路拥挤？

　　His carelessness led to the serious consequence.

他的粗心造成了这个严重的后果。