Fill in the blank with a suitable word

V. Fill in the blank with a suitable word. 1. She was cooking ............... the phone rang. 2. Would you mind ............... I smoked here? 3. Mary used ............... be a good student. 4. Yesterday was ............... hottest day during this month. 5. I sat in the first row so ............... to clearly hear his lecture. 6. she asked me when ............... depart.