Two is it gives you some sense for how concerned parents were about the risks of polio in the community and how much they wanted a vaccine to be developed, such that they gave permission for their children to enter into this trial.
第二是,它能让你了解,父母们对孩子,罹患小儿麻痹症的风险的关心程度,以及对疫苗的渴望程度,这使得他们同意让他们的孩子,参与到这种实验中
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