As is often pointed out, knowledge is a two-edged weapon which can be used ______ for good or evil.
Today’s world is changing rapidly, making _____ necessary for us to continue learning otherwise we can’t keep up with the time.
. ---- It’s a secret _____ you and me.
I think going swimming in my spare time, _____ I think is great fun and good exercise as well as a useful skill.
Thanks to the Internet, large quantities of information are now _____ to us in our home.
. Man must produce more grain to support the _____ growing population on earth.