单项选择题
A．give up their college education B．learn from other students C．feel happy because they are in college D．try hard before giving up
A．there is less trading business B．there used to be more social activities in the old days C．supermarket managers has more problems D．there is less personal contact between manager and customer
A．treating heart attack victims B．releasing people"s fears C．treatment for infertility D．curing cancer