Forget vs. left
forgot his mobile at work.
RIGHT: Peter left his mobile at work.
Many students often say things like, “I forgot my mobile at work”, or “I forgot my wallet in the restaurant.” But these are incorrect. In English, you cannot forget something somewhere. You leave something somewhere. So you would you say, “I left my mobile at work”, or “I left my wallet in the restaurant.”
We can use the word ‘forget’ to express that we’ve left something behind, but for it to make sense in English, you cannot say where you forgot it. In the following example, both uses of ‘left’ and ‘forgot’ are used correctly:
A: Oh no, I forgot my mobile!
B: Where did you leave it?
A: I left my mobile at work.