单项选择题
A.three times as big as B.three times as bigger as C.as three times big as D.as three times gigger as
There is a serious liability（）performance and fuel effi...
单项选择题There is a serious liability（）performance and fuel efficiency.
A.in time of B.in case of C.in terms of D.in honour of
Although recent years have seen（）reductions in noxious ...
单项选择题Although recent years have seen（）reductions in noxious pollutants from individual motor vehicles, the number of such vehicles has been steadily increasing.
A.substantial B.substance C.submit D.subjective
The number of such vehicles（）steadily increasing.A.have...
单项选择题The number of such vehicles（）steadily increasing.
A.have been B.had been C.having been D.has been
