---What’s the matter with John? He has been sitting there for hours.---A postcard from his father_______ an attack of home-sickness in him.
_______, people injured in the earthquake are _______.
Some scientists think there are _______ 2,000 million flashes of lightning per year.
Whenever we are in ______ trouble, we should never lose______ heart.
We all know that, __________, the situation will get worse.
—Can I join the club, Dad? —You can when you _____ a bit older.