He failed the mid-term examination and only then _____ how much time he had wasted. [ ]

The doctor insisted that the boy_____seriously ill and that he _____on at once.

The islands developed on theirown for 80 million years and _______ have many rareanimals found nowhere else.

Quantities of water ________ every day with no people noticing it. [ ]

John opened the door. There _____ he had never seenbefore.