单项选择题
At a rough estimate,Nigeria is（）Great Britain.
A.three times as big as B.three times as bigger as C.as three times big as D.as three times gigger as
单项选择题 There is a serious liability（）performance and fuel efficiency.
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.
单项选择题 The number of such vehicles（）steadily increasing.
