单项选择题
A.for B.to C.by D.as
The combustion of larger molecules,（）have multiple carb...
单项选择题The combustion of larger molecules,（）have multiple carbon-carbon bonds involves a more complex series of reactions.
A.what B.which C.that D.who
All of these alternatives are carbon-based fuels（）molec...
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
The hydrocarbons they do emit are less likely to（）ozone...
单项选择题The hydrocarbons they do emit are less likely to（）ozone.
A.general B.generation C.generate D.generous
