How do you know if something is complementary

When something combines the other is said to be complementary.

Explanation:

Complementary is mainly referred to as combination, that is, when one component goes along with the other. One of the day to day example of a complementary good is bread and butter because bread goes along with butter and thus it makes a good combination.

Complementary in English Grammar means to develop a link. In English Grammar complement falls under a clause. There are three type of complements such as subject complement, object complement as well as adjective complement.