单项选择题
The survey showed that （）numbers of 15-year-olds were already smoking twenty cigarettes a week.
A. essential B. steady C. primary D. substantial
单项选择题 Those old buildings were ______ to make room for a new shopping center.
单项选择题 AIDS is causing great public concern because the（）fatal disease hits primarily young people.
单项选择题 It is not too late, but （）action is needed.
