Fill in each blank with a suitable question word.
1. I don't know _______ to deal with this problem.
2. My sister wondered _______ to buy the best cakes.
3. Could you tell me _______ to do to get on well with my new neighbours?
4. They asked _______ to take out the rubbish, at 5 or 6 p.m.
5. He can't decide _______ to give his books to.