[E]OG-68，请指点！

excellent

68. Often visible as smog, ozone is formed in the atmosphere from hydrocarbons and nitrogen oxides, two major pollutants emitted by automobiles, react with sunlight.
A.ozone is formed in the atmosphere from
B.ozone is formed in the atmosphere when
C.ozone is formed in the atmosphere, and when
D.ozone, formed in the atmosphere when
E.ozone, formed in the atmosphere from

请问Often visible as smog中的as为什么不是like呢？

另外提醒大家，E错的主要原因，撇开句意不说，ozone与recat主谓不一致！

Energy

以下是引用excellent在2004-1-19 18:22:00的发言：
68. Often visible as smog,
请问Often visible as smog中的as为什么不是like呢？

另外提醒大家，E错的主要原因，撇开句意不说，ozone与recat主谓不一致！

提醒得好像不对吧？
often visible like smog什么意思？as prep.查一下字典

halcyon

状语