Present Progressive 3

Fill in all the gaps with the correct form of the present progressive; then press "Check" to check your answers. If you need help, you can click on the "Hint" button at the bottom of the screen. Note that you will lose points if you ask for a hint.
    We (pollute) our environment every day with our activities. Many people (drive) cars when they should be using public transit. As a result, the roads are heavily congested. Cars (idle) for hours in heavy traffic. As well, our factories (pour) clouds of toxic waste into the air. They (produce) things we need but they (destroy) the environment as they do it. The air (become) unbreathable. We need to be more careful in how we live.