1
[ADJ	形容词]首要的;主要的 You use 
primary to describe something that is very important. 
- That's the primary reason the company's share price has held up so well... - 这是公司股票价格一直居高不下的主要原因。 
- I don't think young people's primary aim in life is to get drunk... - 我觉得年轻人生活的主要目标并不是一醉方休。 
- His misunderstanding of language was the primary cause of his other problems... - 他对语言的误解是引起其他问题的主要原因。 
- The family continues to be the primary source of care and comfort for people as they grow older. - 随着年龄的增长,家庭仍然是人们获得关爱和安慰的主要源泉。 
2
[ADJ	形容词](教育)初级的,初等的,小学的 Primary education is given to pupils between the ages of 5 and 11. 
in AM, use 美国英语用 elementary
3
[ADJ	形容词]首先的;最早的;最初的 Primary is used to describe something that occurs first. 
- It is not the primary tumour that kills, but secondary growths elsewhere in the body... - 原发性肿瘤并不会置人于死地,致命的是身体其他部位的继发肿瘤。 
- They have been barred from primary bidding for clients. - 他们被禁止对客户进行最初的投标。 
4
[N-COUNT	可数名词](美国)初选,预选 A 
primary or a 
primary election is an election in an American state in which people vote for someone to become a candidate for a political office. 
- ...the 1968 New Hampshire primary... - 1968年新罕布什尔州的初选 
- She won the Democratic primary... - 她在民主党的初选中获胜。 
- New York holds its primary election on Tuesday. - 纽约州将在星期二举行预选。