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.
except
Preposition
—
Not including.
Except mercury, most metals are solids.
except
Conjunction
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Not including; but.
except
Verb
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To exclude.
b
Noun
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B is the second letter of the alphabet.
"b" comes after "a" but before "c"
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In some schools, a B is a fairly high grade.
Charles got a B in his maths test.
gate
Noun
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A gate is like a door in a fence. It opens to let people go through the fence.
Please open the gate for me; my hands are full.
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In computers and logic, a gate is something that gives a simple yes-or-no answer from two (or one, or more than two) yes-or-no things coming into it.
We need one more "and"-gate here so that it will give the finished answer.