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Hi..my friend asked me to go for dinner tomorrow.. Which is the correct sentence to reply her:
I will let you know by tomorrow afternoon OR
I will let you know tomorrow in the afternoon?
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It depends on what you mean.

I will let you know by tomorrow afternoon. = I will inform you today or tomorrow before noon.
I will let you know tomorrow in the afternoon. = I will inform you between noon and 5 pm tomorrow
Comments  
Mehkayto reply her:
to reply to her:
Students: Are you brave enough to let our tutors analyse your pronunciation?
 AlpheccaStars's reply was promoted to an answer.

I will let you know by tomorrow afternoon