兩級

He was my senior at Yale by two years. 他是耶魯大學(xué)比我高兩級的學(xué)生。

The project took place during the teacher's in-school probationary teaching period, and had two stages. 研究共分二階段進(jìn)行。

In some cases, a two-stage severe hydrotreater using Ni-Mo and precious metal catalysts in the first and the second stage respectively can be used. 有時更得采用二階段制程，前后段分別使用鎳鉬和貴金屬觸媒。