We form the perfect aspect of a verb with HAVE plus the third form (past participle) of the verb.1) Is there a grammatical rule that governs the usage of 'has' instead of 'is'?
2) is it incorrect altogether if 'is ripened' is used?
We form the passive voice of a verb with BE plus the third form of the verb.
We could say "The fruit is ripened by putting it into a warm dark room".
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