refinement GRE专八

1.All programs have bugs and need endless refinement.

所有程序都有漏洞，都需要不断进。

2.It is possible to add a few useful refinements to the basic system.

对基本系统进行一些有良是可能。

3.A greater refinement of the categorization is possible.

进行更加精细分类是可能。