单项选择题
The attack of the World Trade Center will leave a （） impression on those who have witnessed the explosion.
A．long B．forever C．lasting D．lively
单项选择题 We must try to （） the best of our moral values for our children and grand children.
单项选择题 The survey showed that （） numbers of 15-year-olds were already smoking twenty cigarettes a week.
单项选择题 The full （） of changes in computer technology will be felt within the next few years.
