单项选择题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

单项选择题A．came from INS which keeps the samplesB．were offered by the emperor’s descendentsC．were offered by the emperor’s servantsD．were taken directly from the emperor’s body