Most of us see a doctor ______ when we get a cold or somethingThis won’t cost us a lot

People’s working efficiency usually decreases more or less when the temperature _________ 35℃ or even higher.

Evidence has been found through years of study _____children’s early sleeping problems are likely to continue when they grow up.

When our teacher heard of the news, he was too angry to say ___________.

My mother used to make breakfast for _____ every morning, but now I do it myself.