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I am quite familar with "once a day"r, "once a week",but not "once in a day"?Howerver , a sentence in my article"The effluent pH and TP were determined once a day",was changed by the editor into"...........once in a day"?
Is there any difference between "once "and "once in"? thank you in advance of.
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blackcheetahIs there any difference between "once "and "once in"? thank you in advance of.
Yes. 'Once a day' is natural; 'once in a day' is normally not.
But "once in a day","once in a week" ect. are also popular in network. For example:
1. What Happens if You Only Brush Your Teeth Once in a Day? a title in "eHow health."website.
2. there is a song called "once in a day"
Now i am totally confused by the editor? Is there any difference between them?
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The Corpus of Contemporary American English has 556 citations for 'once a day' and just two for 'once in a day'. 'Once in a day' is not impossible, but it is clearly far less common than 'once a day'.
Thank you for your kindness! Do you think I should insist my sentence and not use "once in a day"?
In a scientific article, "once per day" referring to the frequency of a measurement, is apporpriate.
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Thank you very much! Wish you happy Christmas in advance!