class、degree、grade与rank这些名词均有“级、等级”之意。
class : 含义广泛，指人或物按优劣划分的等级，也指学校中的年级或班级。
- Whenever I travel by train, I always travel first class.
我每次乘火车旅行都坐头等车厢。 - When it comes to mathematics, he's in a different class to his peers.
说到数学，他和他的同龄人不在一个级别上。
degree : 指程度、范围不同，社会地位的高低。也可指形容词或副词的级。
- This job demands a high degree of skill.
这项工作对技术的要求很高。 - There isn't the slightest degree of doubt that he's innocent.
毫无疑问，他是无辜的。 - I have to warn you that there's a degree of (= some) danger involved in this.
我必须警告你这里面有一定的危险。
grade : 指按地位或优劣划分的等级，既可指人又可指物。
- He's suffering from some kind of low-grade (= slight) infection, which he can't seem to get rid of.
他感染程度较轻，但好像就是无法痊愈。 - There's some really high-grade (= high quality) musicianship on this recording.
这张唱片体现出高超的音乐技能。 - Bill has been on the same grade (= his job has been of the same level of importance, or he has had the same level of pay) for several years now.
比尔在同一个职位上已经呆了好几年了。
rank : 指人在社会中的地位或等级，尤指军队中的军衔。
- senior/high/junior/low rank
高／低级职位 - He has just been promoted to the rank of captain.
他刚被提升为上尉。 - Ministers of cabinet rank receive a higher salary than other ministers.
进入内阁的部长比其他部长的工资高。
