The federal rules aimed at protecting human subjects of medical experiments were established to ensure that patients must be warned of potential risks and an independent panel would evaluate the experiment before it was conducted.
The federal rules aimed at protecting human subjects of medical experiments were established to ensure that patients must be warned of potential risks and an independent panel would evaluate the experiment before it was conducted.
(a) .... (b) must be warned of potential risks and that an independent panel (c) are warned about potential risks and that an independent panel (d) will be warned about potential risks and an independent panel would (e) would be warned of potential risks and that an independent panel would 答案选E,不是ensure后面应用should虚拟,接动词原形吗