单项选择题
A.twice as expensive as B.as twice expensive as C.as expensive twice as D.expensive as twice as
Ethanol and methanol have important advantages（）other c...
单项选择题Ethanol and methanol have important advantages（）other carbon-based alternative fuels.
A.on B.over C.by D.with
On the other hand, alternative fuels do have（）.A.drawba...
单项选择题On the other hand, alternative fuels do have（）.
A.drawbacks B.setback C.drawer D.backward
There is a growing realization that the only（）way to ac...
单项选择题There is a growing realization that the only（）way to achieve further reductions in vehicle emissions is to replace conventional diesel fuel and gasoline with cleaner-burning fuels.
A.effective B.efficient C.sufficient D.Supplement
