Once out of the earth’s gravity, the astronaut is by the problem of weightlessness.
We must keep our room clean. Dirt and disease go ____________, you know.
--Could I use your bike, Jack? --Of course, you____________.
Helen is much more kind to her youngest child than to the others,___________ of course, make the others unhappy.
--____________? --He is tall and strong.
She suggested to the police in the police station that__________.