We could randomly divide them into two groups, and then we could have one group that is a non-intervention control group to compare to, which we can’t do with, say, breast cancer, because everyone gets treated.
于是我们将他们随机分成两组， 然后我们本可以将非干预组的病人 与像乳癌这样的癌症作比较， 但我们不能这样做，因为乳癌患者每个人都要接受治疗。