历史记载，伊尹与（）有关、汤液的发明与使用、使单味药向（）转变，促进了（）的诞生，为临床用药经验进一步研究和总结提供条件。
查看答案
As a frame leaves a Layer 3 device，the Layer 2 encapsulation information is changed from what it was when it entered the device. For what two reasons can this happen？（）
A. The data is moving from 10BASE-TX to 100BASE-T
B. The WAN encapsulation type has changed.
C. The data format has changed from analog to digital.
D. The source and destination hosts are in the same subnet.
E. The source and destination MAC addresses have changed.
光电倍增管是（）扫描仪常采用的光电转换器件。
A. 平台式
B. 滚筒式
C. 手持式
D. 反射式
微信支付 
支付宝支付