计算题:某药物添加剂,在配合饲料中允许使用量为4mg/kg,该饲料添加剂商品含有效成分为4%,试计算该添加剂原料在配合饲料中的用量。(计算结果格式为0.00%)
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急性毒性试验选择动物的原则()。
A. 对化合物毒性反应与人接近的动物
B. 易于饲养管理
C. 操作方便
D. 易于获得,品系纯化,价格低廉
E. 以上都是
1997年中国环境状况公报公布,黄河面临污染和断流的双重压力。70年代年黄河断流的年份最长历时21天,1997年长达()天。
A. 133
B. 218
C. 226
A developer is designing a web application that makes many fine-grained remote data requests for each client request. During testing, the developer discovers that the volume of remote requests significantly degrades performance of the application. Which design pattern provides a solution for this problem?()
A. Flyweight
B. Transfer Object
C. Service Locator
Dispatcher View
E. Business Delegate
F. Model-View-Controller