Something that takes the place of another thing.
When the power went out, we used candles as a substitutive source of light.
當停電時,我們用蠟燭作為替代的光源。
Involving or allowing substitution or replacement.
The substitutive policy made it easy to replace old equipment with new models.
替代政策使得用新型號替換舊設備變得容易。