Why do you often take exercise? — _____ me keep fit.
Today’s young people can’t live without smart phones. They keep their hands on the phones wherever they go, even while they ________ meals.
We don’t know who ____ for the murder, but the policemen will tell us the truth soon.
About _______of the engineers in my company seem to be in their _________．
Mary couldn’t go to the cinema with us because she had to _____ her little brother.