1.
Analysis and Improvement Measures on the Causes of Nonconformity in Ultrasonic Flaw Detection for 60 kg High-Tensile Steel
60kg级高强度钢板探伤不合的原因分析及改进措施
2.
Surface Peeling Analysis of 60 kg/m Grade Rail
60kg/m级钢轨表面起皮缺陷分析
3.
Finite-Element Simulation of Universal Rolling Process for 60kg/m Rail;
60kg/m重轨万能轧制过程有限元模拟研究
4.
Finite Element Simulation Study on Universal Rolling Process of 60 kg/m Steel Rail
60kg/m钢轨万能轧制过程有限元模拟研究
5.
Cause Analysis of Rolling Scar of 60kg/m Rail and the Countermeasures
攀钢60kg/m钢轨轧疤缺陷原因分析及改进措施
6.
Class, class, class;
班级，班级，班级；
7.
Skip from the fourth to the sixth grade.
从四年级跳级到六年级。
8.
Starter , Standard, Professiona
入门级, 标准级, 专业级
9.
(3) the lower level is subordinate to the higher level;
（三）下级服从上级；
10.
Demote from
降级，降职，使……降级。
11.
Triple A [3A ] 3A
级，最佳债券评级［
12.
director of bureau [directorate rank]
局长〔首长级职级〕
13.
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。
14.
They should also have middle-and lower-level schools.
还有中级的、初级的。
15.
The boy was kept back in the fourth grade.
男孩在四年级时留级。
16.
He had to repeat the fourth grade.
他读四年级时留级一年。
17.
extraction fractionation
提取分级（分离），萃取分级
18.
interstage gland
级间密封，级间汽封