- Will you be available at three o'clock tomorrow afternoon? - No. I ______ a lecture then.

Rainforests ____ and burned at such a speed that they will disappear from the earth in the near future.

In a room above the store, where a party_______ , some workers were busily setting the table.

—How long have you been in this office?—Just a few minutes. My cousins__________ here together with me.

 Every possible means ___ to prevent the air pollution, but the sky is still not clear．