It has been proved _______ eating vegetables in childhood helps to protect you against serious illnesses in later life.

—What a smart and hard-working boy he is!—Right. ________ a possibility that he will win the first place in the competition.

---- How’s your new babysitter? ---- We ______ ask for a better one. All our kids love her so much.

--- It’s the fourth time that heavy smog(雾霾) has hit the city this month.--- It’s high time we _______ measures to fight air pollution. 

—Where can I find Martin?Dad is asking for him.—He_______in the backyard chopping wood.