A distinction should be made between the primary and secondary tasks.

要区别主要的和次要的任务。

《新英汉大辞典》

Can we just backtrack a little bit and look at your primary and secondary education?

我们能否稍微回顾一下刚刚提及的你的中小学教育背景？

《柯林斯英汉双解大词典》

Historians use a wide range of primary and secondary sources for their research.

历史学家在研究中使用大量的原始资料和二手资料。

《牛津词典》

"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

This is an unfortunate thing you see throughout education frankly, certainly at the secondary and primary school level where you just insert technology into the classroom and expect to solve problems, that is not in life always the case.

遗憾的是,中小学教育中,就是讲知识然后运用所学的知识解决问题,但是实际生活中不总是这样。

哈佛公开课 - 计算机科学课程节选

So, every time you're exposed to a new vaccine or a new antigen you go through this primary response before you have the secondary response.

所以,每当你接触到新疫苗或是新抗原,在再次免疫之前,机体将会经历这样的初次免疫过程

耶鲁公开课 - 生物医学工程探索课程节选

Dimension 3: boys, girls and adolescents of basic secondary school age not in primary or secondary school.

UNESCO: MEDIA SERVICES

Dimension 2: boys and girls of primary age not in primary or secondary school, distinguishing between those who have never attended primary school, those who have started school late, or those who have participated for a restricted amount of time and who drop out without completing the whole level.

UNESCO: MEDIA SERVICES

Dimension 1: boys and girls of primary age not in primary or secondary school, distinguishing between those who have never attended primary school, those who have started school late, or those who have participated for a restricted amount of time and who drop out without completing the whole level.

UNESCO: MEDIA SERVICES