单选题A single vessel being towed alongside shall exhibit（）.A one all-round white lightB sidelights and a sternlightC only the outboard sidelight and a sternlightD a masthead light，sidelights，and a sternlight

A pilot vessel may continue to sound an identity signal if she is ______.

A.aground

B.at anchor

C.not under command

D.being towed

A single vessel being towed alongside shall exhibit ______.

A.one all-round white light

B.sidelights and a stern light

C.only the outboard sidelight and a stern light

D.a masthead light，sidelights，and a stern light

If a seaplane is not used as a means of transpiration on water but is capable of being used so，it shall ().

A.be regarded as a vessel not under command

B.be regarded as a vessel underway

C.be regarded as a vessel

D.be regarded as a sailing vessel

If practical, when shall a manned vessel being towed sound her fog signal?______.

A.Immediately before the towing vessel sounds hers

B.Immediately after the towing vessel sounds hers.

C.As close to the mid-cycle of the towing vessel’s signals as possible

D.At any time as long as the interval is correct

A partly submerged vessel or object being towed，which is not readily noticeable，shall show ______.

A.yellow lights at each end

B.two red lights in a vertical line

C.a black ball

D.a diamond shape

A vessel or object being towed astern shall display a(n) ______.

A.forward masthead light

B.after masthead light

C.stern light

D.All of the above

A pilot vessel on pilotage duty shall show identity lights ______.

A.at any time while underway

B.while at anchor

C.while alongside a vessel

D.All of the above