Put the verbs in brackets into their correct forms!
1. I would have read the letter if I had known (know) it was from you.
2. If Tony doesn't help in the garden I won't finish (not finish) my work in time.
3 .If you didn't tell (not tell) me about Maxwell's birthday I would forget it.
4. We would have caught (catch) the train earlier if Mary had found her purse.
5. If Susan had learned (learn) the poem she would have known the answer.