今欲配制一升0.01000mol/LK2Cr2O7(摩尔质量294.2g/mol)溶液.所用分析天平的准确度为±0.1mg.若相对误差要求为±0.2%,则称取K2Cr2O7应称准至:()
A. 0.1g
B. 0.01g
C. 0.001g
D. 0.0001g
E. 0.02g
Which two benefits are provided by creating VLANs?()
A. added security
B. dedicated bandwidth
C. provides segmentation
D. allows switches to route traffic between subinterfaces
E. contains collisio