noun
BAD : These traditions took a long period of time to evolve.
GOOD : These traditions took a long time to evolve.
BAD : She needs somewhere to live for a period of time.
GOOD : She needs somewhere to live for a while.
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a (long/short) time/while (WITHOUT period ): 'You can stay here for a while, if you like.' 'Learning a foreign language can take a very long time.'