0 excellent -- 出色的；优秀的；第一流的
She did a first-class job of decorating the living room. 她把起居室装修得棒极了。
1 used to refer to the best possible undergraduate university degree you can get in the UK and some other countries -- （英国大学学位）一级优等的
2 relating to the most expensive and highest quality service on a plane or train, or in a hotel -- （舱位、车厢或宾馆房间）头等的，最高级的
3 If you travel first class in a train, aircraft, etc., you use the best and most expensive type of service. -- 坐（飞机）头等舱（地）；坐（火车）头等车厢（地）
4 the best and most expensive seats on a plane or in a train -- （飞机）头等舱座位；（火车）头等车厢座位
They used to guarantee that a first-class letter would arrive the next day.
Would you like me to find you a seat in the first-class carriage?
"How can you call that a first-class service?" snorted one indignant customer.
We have first- and second-class accommodation on this flight.
It is worth paying extra for a first-class cabin, in my opinion.
I didn't realize I was in first class until the ticket inspector told me to move.
Indeed, configurations combine lambda abstractions (first-class functions), records, environments with mutually recursive definitions and modules.
