“善师四夷者，能制四夷；不善师四夷者，外夷制之”，能最早体现这一思想的是 [ ]

A、《永乐大典》

B、《四库全书》

C、《天演论》

D、《海国图志》

As an extinguishing agent,foam（）.

A.couducts 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 blow ignition temperature