I was very happy to receive lots of nice presents _____ the morning of Women’s Day. [ ]

Can you finish _________ that picture before nine?

I simply couldn’t understand how it _____ that you did so much work within such a short time．

Mr Wang is an excellent teacher. He is ______ to spend a lot of time explaining things to us.

I found ______ not very difficult to keep away from the A/H1N1 Flu.