1.That time can be difficult to determine, and there are many conflicting opinions regarding the most appropriate time to vaccinate.
这一时间很难确定,在何时是正确的免疫时间这一问题上许多观点是冲突的。
3.In fact, other researchers have used the empty viral shell to vaccinate monkeys, and even humans.
事实上,其他学者已经使用空病毒衣壳来免疫猴子,甚至人。
4.Fortunately, in recent years most American egg producers have started to vaccinate their flocks. All companies should accelerate their efforts.
幸运的是,美国最大的蛋品生产商近年来已经开始对鸡群接种。所有的公司都将加快这一工作。
7.In a recent study, however, the number of parents in the US who indicated they would not vaccinate their daughters against HPV increased from 40 to 44 percent.
然而在最近的研究中,有44%的美国家长称不准备给女儿注射HPV疫苗,此前这个比例是40%。