单项选择题
A.the suction stroke
B.the compression stroke
C.the expansion stroke
D.the exhaust stroke
单项选择题 Which of the following operations aboard a tanker must be recorded in the Oil Record Book （）
单项选择题 The lowest temperature at which the vapor formed from a liquid ignites and continues to burn steadily in the presence of an ignition source is called the （）
单项选择题 Which of the following statements describes one of the functions of the ballast system?（）