________ time went by, small clever animals covered the earth and have become the most important animals on the planet.
In the dark forests ________, some large enough to hold several English towns.
Little _____ about his own health though he was very ill.
Well ____ know him and well ____ know me.
_____, he talks a lot about his favorite singers after class.
Never before _______in greater need of modern public transport than it is today.