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.
oil
Noun
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Oil is a liquid that is burned to create heat or used in machines to make them run well.
Gas and oil are essential to running a car.
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Oil is a liquid made of fat that is used for cooking.
Cook the potatoes in oil.
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An oil is a painting made of oil paint.
oil
Verb
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If you oil something, you put clear oil on a machine to make it run well.
She oiled the parts of the gun.