关于自密封瓶内抽吸药液的方法，下列叙述错误的一项是

A．排气时须以食指扶住针栓

B．药瓶内应先注入等量空气后再抽吸药液

C．吸药时针头斜面应向下，空筒容量刻度朝上

D．自密闭瓶内抽药，针头与瓶塞应垂直

E．开启瓶盖后，用酒精棉签消毒瓶塞再抽吸药液

When underway in a channel,you should keep to the（）.

A.middle of the channel

B.starboard side of the channel

C.port side of the channel

D.side of the channel that has the widest turns