Is the expression "harp on about sth" formal, or can be found on every day conversations?
-- To the contrary, it's not at all formal. It's not very common, but it's informal (and well understood).
Is the word "holdup" used to mean the same as "robbery"?
-- It has some other meanings too, but if you said "I can't believe it! I was at the bank when there was a hold-up!" I'd know what you mean. (I believe it has a hyphen.)
Is the expression "Oh, my Goodness" American English?
-- I use it, but I never put the comma and I don't capitalize the G. (And I'm as American as they come.)
How do you call it in English when someone is sighting or blowing because he is fed up of a situation?
And last, are these two sentences right:
Look for the words you don't know in the dictionary
-- Looks good to me if you remember to end with a period.
Please, print the activity and bring it in class on the 26/09/07
Please print the activity (sheet?) and bring it to class on 26/09/07.
[not a teacher]