【1】per 为介词：主要用来表示比率、价格，速度，比例等每，每一

Rooms cost £50 per person, per night.房价每人每晚50英镑。

These apples cost five yuan per kilogram.这些苹果每公斤五元。

The vessel tax of anchorage is 5,000 dollars per year.这艘船的停泊税一年是五千美元。

Tickets to the concert are $50 per head!这场音乐会的门票价格是每人五十美元。

The goods were shipped per steamer.货物由船舶运送。

This car runs 60 miles per hour每小时60英里

Social Security refused to pay her more than £17 per week.

社会保障部门拒绝每周向她支付17英镑以上的钱。

Buses and trains use much less fuel per person than cars.  

公共汽车和火车的人均燃料耗费量比轿车小得多。

【2】every 为限定词：每一/每一个主要用来指在特定的一个(数量大于等于3的）群体中的每一个的概念，且这个群体的数量必须是大于或者等于3个。同时强调整体概念。

She knows every student in the school.她认识学校里的每一个学生。

I could hear every word they said.他们说的每句话我都能听见。

We enjoyed every minute of our stay.我们逗留期间每一分钟都过得很愉快。

 Every village has a green, a church, a pub and a manor house.

每个村庄都有一片绿地、一座教堂、一间酒馆和一座庄园宅第。

Record every expenditure you make.  记下你的每一笔花销。