Find and correct the mistakes in the following sentences.

I forgot have discussed this topic with you.
1. forgot
2. have
3. discussed
4. with
Had won many maths competitions helped me win a place at university.
1. Had
2. won
3. helped
4. at
Nam regretted not having choose a more interesting Course at university.
1. regretted
2. having
3. choose
4. at
He was proud of had won the first place at the biology competition.
1. was
2. of
3. had
4. at