The students are warned not to talk about anything ______ to the accident that happened the other day in the school.
I have many friends, _____ some are businessman.
____ is certain, though, is that the mystery of Tutankhamun’s tomb has never been fully explained.
Some time after the rockets and the space shuttle are _____, the rocket will _____ the space shuttle and ____ the sea.
London people always take umbrellas with them, just _______ it rains.
Experts suggest that teenagers spend at least 30 minutes exercising, five times a week. Walking and riding your bike _____ , and ______.