英语语法学习：时间状语从句

1)___________ I opened the door, I found everything was gone. 2)My mother was cooking _____________ I was reading. 3)She didn’t leave Paris _______________ she retired. 4)It was 20 years since they __________________ (marry). 5)_____________ he arrives, I’ll tell him. 6)Think first ___________ you lose patience with someone you love.