Everyone in our class was working hard and doing what we could ________ a good university. 

_________ the global financial crisis, the Chinese government has taken many measures _______ people ‘s life to deal with it. 

There was a terrible noise _______the sudden burst of light.

In Singapore, people who litter or dirty the street are most likely ___________.

— I regret _______ you that you failed the exam.  — How I regret _______ so much time playing computer games.