As compared to carbon dioxide，dry chemical has which advantage?（）.

As an extinguishing agent，foam（）.

A.conducts electricity
B.should be directed at the base of the fire
C.is most effective on burning gases which are flowing
D.extinguishes by cooling oil fires below ignition temperature

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Any ship damaging a pipe could（）an immediate danger of fire.

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

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