Englishfor English speakers
classroom
Noun
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A classroom is a room used for instruction and teaching, usually a room in a school.
in
Preposition
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Used to show that something is inside something else.
The cat is in the box.
—
Used to show that someone is at home, or is available.
Is John in?
The Doctor is now in.
—
Used to show movement towards the inside.
The rain came in through the window.
tier
—
noun
a worker who ties something
—
noun
any one of two or more competitors who tie one another
—
noun
one of two or more layers one atop another
tier upon tier of huge casks
a three-tier wedding cake
—
noun
something that is used for tying
the sail is fastened to the yard with tiers
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noun
(= grade)
a relative position or degree of value in a graded group
lumber of the highest grade