A.To better explain how to use that product. B.To help reduce the promotion cost of that product. C.To induce more famous people to use that product. D.To get TV viewers to remember that product.
拍照语音搜题,微信中搜索"皮皮学"使用
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参考解析:
知识点:
皮皮学刷刷变学霸
举一反三
【单选题】阶跃信号具有“起始”一个函数的能力。如果某函数为 f ( t ) ,起始时间为 t 0 ,则其数学表达式是