道路在这儿分为两叉了。

The road divaricates here.

youdao

So, they developed this bifurcated tool, which would be appl--you'd put the stuff on the surface of the tool and then you'd scratch the skin in a certain way so that you could produce sort of a reproducible introduction of the vaccine into the skin.

所以他们发明了一种分为两叉的工具,把疫苗抹在这种工具表面上,然后以某种方式在皮肤上刮,这样就能将疫苗,重复不断地引入到皮下

耶鲁公开课 - 生物医学工程探索课程节选