We cancelled our flight because the weather was bad. -> We cancelled our flight because of the bad weather. Ex 1. Combine these pairs of sentences. Use "Because" 1. The water is highly polluted. We can not swim in this part of the river. → Because the water is highly polluted, we can not swim in this part of the river. 2. It started to rain. We could not keep on cleaning the beach. ->. Because. It started to rain, we could not keep .an. ..sleaning. the beach. 3. We want people to be aware (ý thức được) of the problem of pollution. We have "a green week" three times a year. 4. Mr. Minh is admired. He spends all his life to protecting the environment. 5. The area around the beach is full of trash. No one wants to go swimming or sunbathing there. 6. I have a broken leg. I fell over while I was playing basket ball.