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is slowing down. ( )3. Four babies are born every second in the world. ( )4. In one year, people have to find food for over 350,000 mouths more. ( )5. A big problem caused by the population will appear by the year 2021. Unit 3 Ⅰ . 15 BCBCA Ⅱ . 1. She found large crowds of people had gathered in the streets. 2. The medicine will cure your headache. 3. There are a great number of traffic problems 4. She hopes she will have a chance to get a new job. 5. Standing on the top of the building, the whole town can be seen. Ⅲ . 15