A．too much exercise often leads to a shorter life spanB．American football is too violent to be good for one’s healthC．to exercise when one is young doesn’t guarantee a good health when one is olderD．Harvard students are physically inferior to students from other universities
A．too much exercise often leads to a shorter life span
B．American football is too violent to be good for one’s health
C．to exercise when one is young doesn’t guarantee a good health when one is older
D．Harvard students are physically inferior to students from other universities