Scientists are convinced _______the positive effect of laughter ______ physical and mental health.
The chances of discovering life on Neptune are about a million _____.
I _____ her not to walk on the thin ice but she would not listen to me.
She is making herself ill with _____ over her son's future.
The microphone enabled them to keep in touch, in other words, it made it _____ for them to contact each other.
In spite of the thunderstorm, the children slept _____ all night.