既善涌吐痰涎，又善截疟的药是（）

A.胆矾

B.莱菔子

C.人参芦

D.瓜蒂

E.常山

When whistle signals are used for launching lifeboats，one short blast means（）.

A.use the float-free method only

B.lower all boats

C.raise all boats

D.drill is over，secure all boats