there are cases of which the similar word pair comprises of a noun and a verb. Before we continue, remember that a noun denotes an object, idea, person, or place. A verb denotes an action or state.

Water pollution can affect marine life.

The mutant sharks are the effect of pollution on marine life.

The present perfect is a verb tense which is used to show that an action has taken place once or many times before now. The present perfect is most frequently used to talk about experiences or changes that have taken place, but there are other less common uses as well. Read on for detailed descriptions, examples, and present perfect exercises.

I have seen that movie twenty times.

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Grammar any member of a class of words that modify nouns and pronouns, primarily by describing a particular quality of the word they are modifying, as wise in a wise grandmother, or perfect in a perfect score, or handsome in He is extremely handsome. Other terms, as numbers ( one cup; twelve months ), certain demonstrative pronouns ( this magazine; those questions ), and terms that impose limits ( each person; no mercy ) can also function adjectivally, as can some nouns that are found chiefly in fixed phrases where they immediately precede the noun they modify, as bottle in bottle cap and bus in bus station.

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Here you have a set of wonderful worksheets where you can practice «Present Perfect» playing a game.