One of my teachers told me not to use the phrase COME AGAIN when you missed something to hear. He did not explain why…
Was it true?
If I was not able to hear what you’ve said, I should not use Come Again?
Hi,
That expression is casual and would be perfectly acceptable to say to someone you know well. More formally you would say: I didn’t quite catch that or Do you mind repeating that/saying that again? Another casual expression used to people you know would simply be: ‘Sorry’ said in a questioning manner.
Alan
I see. Thank you so much sir for your explanation; however, according to my filipino teacher, that phrase has a bad connotation. Is it also true?
Hi,
All I can say is that for me there is no ‘bad connotation’ with this expression.
Alan
Tell your teacher to get his mind out of the gutter :)))
He’s probably referring to the homonym of the word “come”: “cum”, so he thinks that everytime someone says “come”, they allude to “cum”. But as Alan indicates, noone thinks of this allusion when they say or hear “come again”.
Sir, thank you so much! 
I see. Sir now its really clear to me. Thank you to you as well.