Girls are advised to begin testing within three years of when they first have sex, or in any case no later than twenty-one.

VOA: special.2009.11.25

The first thing is testing shallow equality.

但是这是什么意思呢？

麻省理工公开课 - 计算机科学及编程导论课程节选

These experimental AIDS vaccines are the first from Africa to reach testing in people.

VOA: special.2009.07.29

It is the first malaria vaccine candidate to have large success during early testing.

VOA: special.2010.04.20

They first started testing out songs together while on a trip to Fez,Morocco.

VOA: special.2009.04.10

The WHO authorized drug manufacturers to begin testing possible vaccines, and the first human trials began a month later.

VOA: standard.2009.12.25