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 The full （） of changes in computer technology will be felt within the next few years.
单项选择题 Because of a recent obstacle in production, sales have dropped and accordingly profits have （）.
单项选择题 Shy people never （） set out to attract attention of other people.
