单项选择题
A.fine
B.imprisonment
C.suspension or revocation of tankerman's document
D.All of the above
单项选择题 A tank which is NOT completely full or empty is called（）.
单项选择题 A tank vessel transferring non-flammable hazardous cargo in bulk must display warning signs. These signs must（）.
单项选择题 A SYSTEM OF CLEANING THE TANKS BY WASHING THEM WITH THE CARGO OF CRUDE OIL WHILE IT IS BEING DISCHARGED is known as（）.