四，1 .Africa's deserts are expanding fast .Thousands are dying. Millions more are refugees.非洲的沙漠正在迅速擴大，數(shù)以千計的人正在死亡，數(shù)百萬人成為難民。

2 . Scientists have been warning the world about this for many years and if people had acted quickly back then , they would have stopped today's disasters but they did nothing.科學家們?yōu)榇艘呀?jīng)警告人們許多年了如果當時人們可以迅速采取行動他們就能阻止如今的大災難,但他們卻無動于衷。

3 . There is also new fuel technology .Today this runs the world's three billion vehicles ， and it produces no CO2 at all-nor any other kind of pollution我們還有新的燃料技術，如今世界上三十億輛汽車以此為動力，它既不產生二氧化碳，也不產生任何其他污染。