—Growing population resulted in growing rubbish.—There is ______that rubbish will become the major threat to human beings in future.

Reading the job ad．he wondered whether he was ____ to apply for it．

The situation forced my mother and I exchanged our roles as child and caretaker, making me grow up much faster than the _____ child.

—The guard keeps         watch at the gate.—So he does. Only those         knows well could be let in.

That room is 20 square meters. This room is three times as        .