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單項選擇題

An oxygen indicator can be used to determine if there is（）.

A.sufficient oxygen in a compartment to support life
B.combustible gases present
C.hydrogen gases present
D.All of the above

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單項選擇題

Anchoring and fishing in this area are（）.

A.danger
B.dangerous
C.dangerously
D.dangering

單項選擇題

Any ship damping a pipe could（）an immedidate danger of fire.

A.meet
B.face
C.be in front of
D.follow