X.
1. If we plant more tree, the air will be fresher.
2. If we use fewer cars, we will reduce pollution.
3. If we cycle to school every day, we will keep fitter.
4. If we used recycled products, we will save money.
5. If people throw rubbish into the right bin, they will keep the environment clean.
6. If we turn off the tap when brushing the teeth, we will save a lot of water.
7. If people travel more by public transport, the harmful gases in big cities will be
reduce.
8. If we start at six, we will arrive there before noon.
9. If the boy eats so many green apples, he will be ill.
10. If we use reusable bags for shopping, we will reduce waste.

=>