Doctors who suspect a patient has Alzheimer's must test the person for many other physical problems first.

VOA: special.2009.09.15

While at the same time as I say congratulations, I want to remind you that I think it comes as no surprise given the lateness of Labor Day this year that this first test came rather early and for many of you much of this material you had seen in high school.

当我对你们表示祝贺的同时，我也想提醒你，今年晚来的劳动节,并非是什么惊喜,第一个测试来的比较早,你们中的绝大多数在高中已经见过了。

麻省理工公开课 - 固态化学导论课程节选

For the first time, scientists around the world had a limitless number of cells they could use to test the effects of diseases, medicines and chemicals.

VOA: special.2010.07.21

Jonas Salk used these HeLa cells to test the first vaccine for polio.

VOA: special.2010.07.21