目前规模化养猪场使用最多的饮水器是（）

A. * * 式饮水器

B.吸吮式饮水器

C.自流式饮水器

D.杯式饮水器

Five or more short blasts on a vessel’s whistle indicates that she is（）.

A.in doubt that another vessel is taking sufficient action to avoid a collision

B.altering course to starboard

C.altering course to port

D.the stand-on vessel and will maintain course and speed