第23题: [单项选择]Why is the tsetse fly a problem in Africa A. People do not like the sound it makes. B. It eats food that people need. C. It has killed many cattle herds. D. It can destroy the crop there. 参考答案:C 答案解析:[分析] 推理题。文章第三段说采采蝇能致动物生病,在某些地方甚至可能摧毁整群家畜,可推知C项为答案。