1、A descent by stages or steps.
遞減，下降一種逐級或逐步的遞減，下降

2、A descent by stages or steps
遞減，下降一種逐級或逐步的遞減，下降

3、We must proceed by stages from the simple to the complex.
我們必須經歷由簡單到復雜的階段。

4、The access road to the dam was arranged by stages and layers.
上壩施工道路分期、分層布置；

by stages翻譯