在两种导电介质的分界面处，电场强度的（）保持连续.
A.切向分量
B.幅值
C.法向分量
D.所有分量
参考答案：A
Mr Black ___China since the summer of 1998. [ ]
A. has been to
B. has been in
C. has come to
D. came to
躯（肢）体固定气囊由躯体气囊、肢体气囊、颈托、（）组成。
A、固定装臵
B、抬升装臵
C、抽气泵
D、拖行装臵
