A、<img width="63" height="28" src="http://img.wangxiao.cn/examfiles/imgcache/attached/image/20140605/20140605151357_2205.png" />

B、<img width="63" height="28" src="http://img.wangxiao.cn/examfiles/imgcache/attached/image/20140605/20140605151406_5356.png" />

C、exdx

D、exIn xdx