根据《全国消防条例》的规定，火灾危险性较大并且距离公安消防队较远的各类开发区、工业园

在△ABC中，a=3，b=7，c=5，则cosB=______．

水源选择的原则是（）

A.水质良好

B.水质充足

C.经济技术合理

D.便于防护

E.以上答案都是

— If he _____, he _____ that poisonous food.

— Luckily he came back to life immediately. [ ]

A. was warned; would not take

B. had been warned; would not have taken

C. would be warned; had not taken

D. would have been warned; had not taken

直流锅炉有那些特点？

简述融资租赁谈判过程中的复杂性。