phases
phases , phasing , phased
phase in
If a new way of doing something is phased in, it is introduced gradually.
The reforms would be phased in over three years.
改革将在三年内逐步实施。
phase out
If something is phased out, people gradually stop using it.
They said the present system of military conscription should be phased out.
他们说现行的征兵体系应该逐步淘汰。