下列物质中含有共价键的离子化合物是 [ ]
A．KOH
B．MgCl2
C．CO2
D．CH4
答案：A
_______ the illegal mobile WAP sites worries many parents.[ ]
A. The children's surfing
B. The children surf
C. The children surfing
D. The children have surfed
在成人，出现休克体征时的出血量占总循环血量的（）
A.10%
B.15%
C.20%
D.25%
E.30%
