None of these do we have vaccines for, and it's turned out that sexually transmitted diseases for a variety of reasons, we'll come back to later, are particularly difficult to develop vaccines for.

这些病我们都没有疫苗,已经证明,对于性传播疾病,有很多原因使得,我们稍后回来再讲,针对这类疾病的疫苗特别难做出来

耶鲁公开课 - 生物医学工程探索课程节选

It can help us specify, add specificity to our conversations.

它能帮助我们特别说明一些情况，或者在谈话中更具有针对性。

That's what课堂 - SpeakingMax英语口语达人