The matter__________your study surely requires__________carefully.
—You have finished two cakes? —Yes. But the second was _____ little bit small, so may I have ___ third one?
_____ underground for 2 years, David says the worst thing is not the danger but the darkness.
She ____ have left school, for her bike is still here.
According to our school rules, no student ____ be permitted to carry mobile phones in class.
You have no idea what I have had to _____ during the last few months.