foremost:

adj. 最重要的；最先的

adv. 首先；居于首位地

It is first and foremost a trade agreement.

它首先是一项贸易协定。

This question has been foremost in our minds recently.

近来我们的心目中一直认为这个问题最重要。

He does a little teaching, but first and foremosthe's a writer.

他干一点教学，但首要的是写作。

He was one of the world's foremost scholars of ancient Indian culture.

他是世界上最出色的/卓越的/优异的/杰出的的古印度文化学者之一。

primary:

adj. 主要的；初级的；基本的

n. 原色；最主要者

We turn now to our primary question.

我们现在转到我们的主要问题上。

It is always women who are the primary carers.

一直由妇女做主要的看护人。

Computers are now commonplace in primaryclassrooms.

计算机如今在小学教室里很普遍。

It comes in bright primary colours that kids will love.

它的颜色都是孩子们喜爱的亮丽原色。