4. Make sentences positive or negative.

1. People (to get) resources from the earth.

1. Consumers (to buy) goods from manufacturers.

1. We (to study) economics.

1. The economist (to study) consumers' behaviour in the service markets.

1. The plant (to process) agricultural products, it (to manufacture) machines.

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6. Industry and agriculture (to use) fuel.

6. I (to study) medicine.

6. Teachers (to study) labour markets.

6. It (to be) possible to predict prices for essential goods.