Virtual goods have become the company's primary source of profits.

网络虚拟物品成为这家公司最大的利润来源。

The United States will remain the primary source of clean-energy innovation.

美国将依然保持清洁新能源的主要输出国地位。

The primary source of his identity is who he is—his father and his birthplace.

帕普的身份的主体是他的父亲和他的出生地。

The course is based on careful readings of primary source documents, with commentaries.

本课程需要对基本阅读材料进行仔细的阅读，然后进行评论。

It`s best to consume organic vegetables and fruits as your primary source of alpha-carotene.

最好以有机蔬菜和水果作为α-胡萝卜素的首要来源。