单项选择题
All of these alternatives are carbon-based fuels（）molecules are smaller and simpler than those of gasoline.
A.which B.who C.what D.whose
单项选择题 The hydrocarbons they do emit are less likely to（）ozone.
单项选择题 Ethanol is commonly used as a gasoline supplement, but it is currently about（）methanol.
单项选择题 At a rough estimate,Nigeria is（）Great Britain.
