1、 The historian searched for primary sources of information about the past、历史学家寻找有关过去的原始资料来源。
2、 A primary cause of Tom's failure is his laziness、懒惰是汤姆失败的主要原因之一。
3、 The primary meaning of the word isn't used now， but you can look it up in a big dictionary、这个字的本义现在不用了，但你可以在大字典里查到。
4、 A primary school is the first school you go to、小学是你上的第一个学校。