The signal given to commence lowering the lifeboats is（）.

A . that a distress message will follow B . a request for assistance in searching for a man overboard C . an urgent warning about a cyclone D . All of the above

A . horizontal motion of a white flag B . letter K in Morse code given by light C . code flag S as a hoist D . firing of a white star signal

A . 3 white star signals B . Horizontal motion with a white flag C . Vertical motion of a white light D . Code letter K by blinker light

A . vertical motion of white flags B . vertical motion of a white light or flare C . firing of a green star signal D . None of the above

A . Place both fists in front of the body with the thumbs pointing outward each other B . Clasp hands in front of your body C . Extend arm with the palm down and and hold this position rigidly D . Extend arm with the thumb pointing up, and flex the finger s in and out

A . Extend arm with the palm down and and hold this position rigidly B . Place both fists in front of the body with the thumbs pointing outward each other C . Clasp hands in front of you body D . Extend arm with the thumb pointing up, and flex the finger s in and out for as long as the load movement is desired

A . Extend arm and point finger in the direction to move the boom B . Extend arm with the thumb pointing downward and flex fingers in and out C . With f rearm vertical and forefinger pointing up,move hand in small horizond circles D . With arm extended downwards and forefinger pointing down,move hand in small horizontal circle

A .  packetization B .  quantization C .  decoding D .  sampling

A . involution B . encoding C . sampling D . quantization E . compression F . companding

A . Extend arm with the thumb pointing up and flex the fingers in and out B . Place both fists in front of the body with the thumbs pointing upward C . With forearm vertical and forefinger pointing up,move hand in small horizond circles D . Extend arm with the fingers closed and thumb upward

A . Use one hand to give any motion signal，and place the other hand motionless in front of the hand giving the motion signa B . Extend arm with the thumb pointing up，and flex the fingers in and out for as long as the load movement is desired C . First tap your elbow with one hand and then proceed to use regular signals D . First tap the top of your head with your fist and then proceed to use regular signal

A . raise the boom B . raise the hook C . raise the boom and hook D . check the boom sto

A . Safety alarm B . Distress alarm C . Fire drill alarm D . General emergency alarm

A . With foremarm vertical and forefinfer pointing up ,move hand in small horizonal circles B . With arm ertended downwards and forefinger pointing down,move hand in small horizontal crecles C . Extend arm with fingers closed and thumb pointing upward D . Place both fists in front of the body with the thumbs pointing outward

A . Place both fists in front of the body with the thumbs pointing outward B . With both arms extended out and palms to down, move arms back and forth C . Extend arm with the palm down and and hold this position rigidly D . Clasp hands in front of you body

A .  involution B .  encoding C .  sampling D .  quantization E .  compression F .  companding

A . a light signal of at least five short and rapid flashes B . one prolonged，one short，one prolonged，and one short whistle blasts C . four short whistle blasts D . two short whistle blast

A．move on B．move off C．move out D．move along

A．encode it by using the binary coding scheme B．quantize it in amplitude C．sample it at discrete time instant D．pass it through a D/A converte