Its important to recognise that 못 V ≠ 안 V, something my 남친’s mum pointed out to me awhile back. She said that Korean’s will generally still know what you are trying to say even if you mix them up, but it’ll make you sound like a foreigner.
시험을 안 했어요 –> I didn’t do the test
시험을 못 했어요 –> I couldn’t do the test
텔레비전을 보느라고 초인종을 안 들었어요 (X)
텔레비전을 보느라고 초인종을 못 들었어요 (O)
I was watching TV so I didn’t/couldn’t hear the doorbell
So 못 is used when you can not do something and 안 is when you didn’t do something, but you could have