分类：教育/科学-学习帮助
问题：英语4.Foryearsscientistshavebeenwo 
4.For years scientists have been worri about the ___________ of air pollution on the earth’s natural conditions. A. effect B. result C. account D. cause 5.The next step in exploring ___________ outer space might be sending people there in ___________ spaceship. A.不填;4.For years scientists have been worri about the ___________ of air pollution on the earth’s natural conditions. A. effect B. result C. account D. cause 5.The next step in exploring ___________ outer space might be sending people there in ___________ spaceship. A.不填; a B. 不填; 不填 C. the; 不填 D. the; the 6.___________ the problem of land erosion getting more serious, the government is searching for a way to deal with it. A. As B. With C. When D. If 
回答：4.For years scientists have been worri about the ____A_______ of air pollution on the earth’s natural conditions. A. effect 影响，一般不是好的B. result结果 C. account数目，账户 D. cause 缘由5.The next step in exploring ____A_______ outer space might be sending people there in ___________ spaceship. 太空作为一种抽象名词，一般视为不可数。a spaceship视为泛指。而且它本身是可数的。A.不填; a B. 不填; 不填 C. the; 不填 D. the; the 6.______B_____ the problem of land erosion getting more serious, the government is searching for a way to deal with it. A. As B. With C. When D. If as可以引导非限制性定语从句，但是必须有从句本身的谓语，事实上横线后面的从句没有谓语，getting是非谓语。这里应该使用with的伴随状语，用现在分词，表示一种一直存在的状态、情形。一般起一种衬托、渲染的功能。Clear?