Onun adresini bilseydim, ona yazabilirdim.
- If I knew his address, I could write to him.
Bunun seni bu kadar üzeceğini bilseydim bundan bahsetmezdim.
- If I knew it was going to upset you so much, I wouldn't have mentioned it.
... knew before. ...
... a pretty good guess about what you do when you go to the toilet. I'm pretty sure I knew ...