Question

if i (to know) that you were ill last week i (to go) to see you​

Answer 1

If I had known that you were ill last week, I would have gone to see you.​ (Если бы я знал, что ты болел на прошлой неделе, я бы пошел тебя проведать.)

Answer 2

If I had known that you were ill last week, I would have gone to see you.​

Желаю удачи!