___is certain is ___prevention is more important than treatment .
Now the question that you must carefully consider is ____ can be put into practice.
If he had decided where to go, he ___ on his way at present.
She can always create an atmosphere for her students, ___ allows them to talk freely with each other.
We are said to be living in ____ Information Age, ___ time of new discoveries and great changes.
—Hi, Terry, can I use your computer for a while this afternoon?—Sorry. ______