What’s the low-carbon life style like –Save_______ energy, produce ________ carbon.

Hurry up, or we will miss the sea lion show in the Ocean Park.—– ______. We still have fifteen minutes before the show begins.

If it isn’t him, who________ it be?

It is thought that one billion people I the world,________is half the word’s workers, earn their living by farming.

Most environmental problems exist because______measures for preventing them have not been taken in the past.[ ]