Some teachers often give their students too much work to do, ________that they will thus improve their school grades. [ ]

I have no idea what _____ while I was asleep

Sorry, I’m busy now. If I ___ time, I would certainly go for an outing with you

________ book named Harry Potter is ________ good friend of mine.

The Internet connection for the entire area _________ when there was a sudden power cut yesterday.[ ]