Most of the few U.S.airports that possess body scanning capability are using the technology for secondary screening of passengers who warrant closer examination by TSA officers.

VOA: standard.2009.12.30

Actually there are two discount rates; there's primary and secondary.

事实上，这里有两个贴现率；,一级贴现率和二级贴现率。

耶鲁公开课 - 金融市场课程节选

"The president has called for focusing in on what it really takes to be successful in work and in college, and he has called on America's educational institutions, primary and secondary educational institutions, to do whatever it takes to get our kids college ready.

VOA: special.2010.02.25