Q28:

In an effort to reduce the number of fires started by cigarettes, a major tobacco company is test-marketing a cigarette in which thin layers of extra paper are used to decrease the amount of oxygen entering the cigarette, thereby slowing the rate at which it burns and lowering the heat it generates.

A. in which thin layers of extra paper are used to decrease the amount of oxygen entering the cigarette, thereby slowing

B. in which they use thin layers of extra paper in decreasing the amount of oxygen entering the cigarette, which slows

C. that uses thin layers of extra paper to decrease the amount of oxygen when it enters the cigarette, thereby slowing

D. for which thin layers of extra paper are used to decrease the amount of oxygen that enters the cigarette, and thereby slowing

这题应该不涉及到现在分词和定语从句的细微差别,关键点是逻辑主语。

看到现在分词,马上要想它的逻辑主语是谁?是否有逻辑主语?如有，这个逻辑主语合适不合适?SC中大多数分词的错误都是无逻辑主语或逻辑主语不合适.

E中using这个动作，显然不是其前面的名词cigarette能发出的,所以排除掉了.

请问C错在哪里啊？

that=in which吧