The running wheel runs along （）on top of the hatch coaming.

单项选择题Could you show me （）to open the hatch covers?

A.why
B.when
C.how
D.what

单项选择题If the hatch cover does not move, （）should be checked.

A. the open valve
B. the stop valve
C. the steam valve
D. the close valve

单项选择题To ensure the safety in operating hatch covers, oil the moving parts （）.

A. monthly
B. every three months
C. once monthly
D. every two months

单项选择题During operation, the （）should check the working condition of the derrick.

A.foreman
B.operator
C.opener
D.stevedore

单项选择题（）has more than ten percent broken wires. Stop using it at once.

A. The cargo runner
B. The cargo block
C. The derrick sling
D. The lashing wire