Farmers can unknowingly spread the infection with their cutting tools.

VOA: special.2009.09.21

and so they just, knowingly or unknowingly, they steal and copy what someone else has already said.

所以他们就，有意识或无意识地，偷窃或者拷贝别人说过的东西。

抄袭是很严重的问题 - SpeakingMax英语口语达人

We did not yet have good methods for screening blood to look for HIV, we didn't have the ELISA technique that I--we talked about in section a few weeks ago and so there was a great concern that there might be other diseases that you'd be passing on from-- unknowingly from this subset of patients that you're isolating the vaccine from.

那时我们还没有一种好的方式,来从血液中筛查出HIV,也还没有ELISA技术,该技术我们在几周前的一个章节中谈到过,因此,那时仍存有,很大的担心,那就是你有可能,在不知情的情况下,被那些病人,感染上其它疾病,因为疫苗就是从他们身上提取出来的

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