若码值PPH是一个整数的补码表示，则该整数的真值为 (121) ：若码值PPH是一个整数的原码表示，则该整数的真值为 (112) 。

A．127

B．0

C．-127

D．-1

A shipmate chokes suddenly，cannot speak，and starts to turn blue. You should（）.

A.perform the Heimlich maneuver

B.make the victim lie down with the feet elevated to get blood to the brain

C.immediately administer CPR

D.do nothing until the victim becomes unconscious