There are two classes, two broad classes of drug sort of type ligands that are defined, agonists and antagonists.

这样的配体药物有两类,目前已经明确的配体药物大体上分为两种,分别是激动剂和拮抗剂

耶鲁公开课 - 生物医学工程探索课程节选

In fact, there are some very old books that show this as the average, the sum divided by two arithmetic mean, but the modern practice is to use the geometric mean.

事实上，一些很老的书籍上,平均的定义就是算数意义的，总的来说被分为两种算数意义，但现代我们多用几何意义。

麻省理工公开课 - 固态化学导论课程节选

Whole life" is more complicated because it builds a cash value according to a schedule and there is both non-participating and participating.

终身人寿保险则更为复杂,因为它会按照购买计划产生现金价值,其中又分为非参与式分红保险和,参与式分红保险两种

耶鲁公开课 - 金融市场课程节选

There are basically two classes of testing.

基本上来说测试分为两种。

麻省理工公开课 - 计算机科学及编程导论课程节选

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