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If they _______ throwing trash into the river, many fish _______.

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If I have time, I _______ some trees in my neighborhood.

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A lot of people _______ trash into rivers and make the water polluted.

Find the mistake.

Governments worldwide (A) are working (B) together to protect (C) the environment for (D) pollution.

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Jane: What about putting more trash cans on the streets?

Mary: _____________.

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We should take a bus often _______ we can help reduce air pollution in the city.

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Burning coal to produce electricity _______ the air.

Find the mistake.

If you don’t pay (A) attention, you will (B) understand (C) the lesson (D).