Englishfor English speakers
a
Determinative
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A is used when the following word could be any of a certain type.
Compare "A book I saw on the shelf" and "The book I gave you yesterday".
a
Noun
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A is the first letter of the alphabet.
The letter "a" comes before "b".
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In some schools, an A is a very high grade.
Ron got an A on his earth science test.
nut
Noun
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A nut is a kind of seed that usually grows on trees inside a hard shell and that people often eat.
Nuts are a good source of protein.
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A metal ring that is screwed onto a bolt (thick screw).
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A crazy person.
case
Noun
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A case is a container to hold something.
He opened the case and pulled out his violin.
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A case is a matter for police or in court.
The judge did not accept his case.
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A case is the form of a noun showing how it is used in a sentence.
The word "he" is in the subject or nominative case.
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A case is a person of a certain kind.
That man is sure a hard case.
case
Verb
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If a police officer cases a house, he or she watches it until something happens.
We were casing a house all night in Brooklyn.