Complete the following sentences with the correct form of the verbs in the box happen reduce save suffer cause throw take be change see 1, If we use less private vehicles, we ____________ the amount of carbon dioxide into the air. 2, If you ____________ the president, what would you do to prevent air pollution? 3, If there were no fresh water left, what ____________ ? 4, If people (not) ____________ rubbish in the street, it would look better. 5, If there wasn't so much light in the cities at night, we ____________the stars more clearly. 6, If the water is contaminated, people____________ from many diseases. 7, If chemicals from factories are dumped into rivers and lakes, they ____________ water pollution. 8, If people want to protect their planet, they should ____________ their habit of using plastic bags for convenience. 9, If we recycle paper, we ____________ 1000 trees a day. 10, If people were more aware of the negative consequences of pollution, they might ____________ actions to prevent it.