非接触式火灾报警器（fire alarm）是根据（）进行探测的

A.烟气浓度

B.烟气成分

C.光学效果

D.烟气流速

A．There was a bomb scare.

B．There was a terrorist attack.

C．A fire alarm was set off by mistake.

D．50 pounds of explosives were found.

If the fire alarm is sounded, all residents are requested to ________ in the courtyard.

A．assemble

B．coverage

C．crowd

D．accumulate

A) assemble

B) converge

C) crowd

D) accumulate

A.感光式探测器

B.感烟式探测器

C.图像式探测器

D.光束式探探测器

A.audible alarm

B.sensitivity adjustment

C.audible alarm ear-piece socket

D.sensitive detection area

A.声能与光能感应式

B.热能与声能感应式

C.接触式与非接触式

D.烟气与热能感应式

A. emergency lighting for occupied areas,navigation lights

B. the driving motors of the emergency bilge pump,fire pumps,and steering gear

C. communications systems and alarm systems

D. all of the above