Mark has come in his raincoat and boots, _____ for rain.

A．preparing

B．prepared

C．to prepare

D．prepares

可解蛇毒治毒蛇咬伤的药物是（）。

A．莶草

B．刘寄奴

C．桑寄生

D．徐长卿

E．以上均不是