physician: The hormone melatonin has shown promise as a medication for sleep
disorders when taken in synthesized form. Because the long-term side effects of
synthetic melatonin are unknown, however, i cannot recommend its use at this time
Patient: Your position is inconsistent with your usual practice. You prescribe many
medications that you know have serious side effects, so concern about side effects
cannot be the real reason you will not prescribe melatonin.
The patient's argument is flawed because it fails to consider that
(D) the side effects of a medication can take some time to manifest themselves
(E) known risks can be weighed against known benefits, but unknown risks cannot
就这两个选项有问题，看了OG的解释，还是没搞懂，希望NN来帮忙解答下，答案在这两个选项中 | 
