气相色谱法测定水中五氯酚时，萃取地表水中的五氯酚用。（）
A．氯仿
B．苯
C．正己烷
D．石油醚
参考答案：C
The flowers were so lovely that they in no time.
A．sold out
B．had been sold out
C．were sold out
D．would sell out
既能祛风解表，又能胜湿、止痛止痉的药物是
A．荆芥
B．防风
C．香薷
D．紫苏
E．桂枝
