A light signal consisting of three flashes means ______.A.I am in doubt as to your actions

A light used to signal passing intentions must be an ______.

A.all-round yellow light only

B.all-round white light only

C.all-round blue light only

D.alternating red and yellow light

A list signal of one white light indicates that the vessel is ______.

A.on an even keel

B.listing about 1° to the side the light is displayed on

C.listing over 5°With the light displayed on the high side

D.listing，and the chutes should be directed to the side where the light is displayed

A．Moths are the most important pollinator in natural environmentB．Insect pollinators have various pollinating effeciencyC．Poor pollinators will visit flowers at a very low frequencyD．UV light is a visual signal for butterfliesE．我不确定

long as ______.

A.white lights are not used

B.red and green lights are not used

C.the signal cannot be mistaken for a signal authorized by the Rules

D.the vessel signals such intentions over the radiotelephone

The Coordinator Surface Search（CSS）in a SAR situation should display by night ______．

A.Deck lights forward and aft

B.A white light over two red lights

C.A red light，white light，and blue light in a vertical line

D.A distinctive signal promulgated by the CSS

f any quarantinable diseases be found．

A.the national flag

B.the quarantine signal

C.the Certificate of Pratique

D.the navigational light

Every ship should hoist ______ when approaching and entering ports.

A.its flashing light

B.the ship’s name

C.its identification

D.its signal letters

red and the middle light is white. Which statement is always TRUE？

A.During the day，she would display three balls in a vertical line

B.If making way，she would show masthead lights at night

C.If at anchor，she need not show anchor lights while displaying identifying lights

D.Her fog signal would consist of a rapid ringing of a bell for five seconds every minute

The balloonists are waiting for ________ weather conditions before taking off.

A considerable

B invaluable

C maximum

D optimum

____the drill is, it is very useful in improving your oral English.

A、 Simple you consider

B、 You consider simple

C、 Simple as you consider

D、 As simple you consider