AT...

at short notice / on short notice - com pouca antecedência

at sixes and sevens (col.) - em uma situação confusa e desorganizada

at source - na fonte

at the appointed time (ou “hour”) - na hora marcada

"The working class did not rise like the sun at an appointed time. It was present at its own making."

E.P. Thompson

at the bottom of the hour - a cada meia hora, no meio de cada hora (1:30, 2:30, etc.)

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