明天就要考试了，希望朋友们能及时回复！（多谢了）

lilya

cr: a drug can be used to some cancer. SInce this cancer is less common, to test this drug, a large number of people will be used and therefore many people will suffer the adverse side effect of this drug. Ask the assumption:
some choices are little confusing:
1. the people who are very likely to contract this cancer is hard to identify in advance.
2. drug test must employ a large number of people in order to be effective
3. drugs that can be effective to some cancer have adverse side effect
Author chose 3 but not very sure.

steven.wei

hi, lilya
i suppose that 3 is better than the other two. 3 is a bridge drugs and side effective. 2, i guess, is unrelated. 1 is not the bridge used as assumption.
do u agree?

ken72

I agree