| 选择方框内适当的选项填入短文空白处（有一项是多余的）。 | |
| A: What are you doing? B: (1) _______ A: Great! Can you tell me something about the book? B: Certainly! It says 1,000 years ago, the world’s population was very small. (2)_______ A: Really? B: Yes, but during the last three or four  hundred years, the world’s population has grown very quickly. Today, it is growing faster than ever before. (3)_______ A: Sorry, I don’t know. B: It’s more than 6 billion. A: It’s so big. (4) _______ B: Yes. If we don’t control the population, there will not be enough space even to stand in on the earth in 600 years. A: (5) _______ | |
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