1.
Class, class, class;
班级，班级，班级；
2.
Skip from the fourth to the sixth grade.
从四年级跳级到六年级。
3.
Starter , Standard, Professiona
入门级, 标准级, 专业级
4.
(3) the lower level is subordinate to the higher level;
（三）下级服从上级；
5.
Demote from
降级，降职，使……降级。
6.
Triple A [3A ] 3A
级，最佳债券评级［
7.
director of bureau [directorate rank]
局长〔首长级职级〕
8.
Schools in the army are divided into those at higher, middle and lower levels.
学校有各级的：高级，中级，初级。
9.
They should also have middle-and lower-level schools.
还有中级的、初级的。
10.
The boy was kept back in the fourth grade.
男孩在四年级时留级。
11.
He had to repeat the fourth grade.
他读四年级时留级一年。
12.
extraction fractionation
提取分级（分离），萃取分级
13.
interstage gland
级间密封，级间汽封
14.
international sea scale
《国际浪级表》国际海况级
15.
nonadjacent level
非相邻级 -分级存储器的
16.
graduated rheostat
分级变阻器,分级电阻箱
17.
Grade 1 coffee is better than Grade 2.
一级咖啡比二级的好。
18.
The landlord class and the comprador class.
地主阶级和买办阶级。