Write the verbs in the appropriate forms to complete the conditions

Write the verbs in the appropriate forms to complete the conditions sentences (Conditional 3)
1) If i had known you needed my help, I ____________ at once (come). Whe didn't you tell me?
2) If I ______________ you at the theatre, I would have come up to say Hello (see)
3) If you ____________ my advice, you wouldn't have made that mistake ( follow)