You _______ all night. You must be exhausted.

Use the watering ________ to water the flowers.

If we continue to pollute the environment, many endangered species _______ extinct.

I _______ a new digital camera. I’m sure we’ll take nice pictures with it.

The government is trying to ______ pollution by using various methods.

We ________ since 2 pm.

You haven’t finished the milk,______?

How long ________ in the rain?

Unfortunately, many wild animals are in _______.

Toxic fumes _______ the air we breathe.

Mark is _______ rubbish.

Acid rain ______ trees and plants.

I could join the club too, ______?

Governments _______ to reduce air pollution for years.

Can I give you a _____?

Paula _______ for hours.

He ______ to clean the pond, he already did it.

He has been studying ______ this morning.

______ factories have new technologies that reduce toxic emissions.