noun
BAD : All of a sudden the child burst in tears.
GOOD : All of a sudden the child burst into tears.
BAD : When the policeman had gone, she broke in tears.
GOOD : When the policeman had gone, she burst into tears.
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burst into tears or break down (in tears) : 'Laura burst into tears and ran out of the room.' 'She still can't talk about the war without breaking down in tears.'