找考题网-背景图
单项选择题

ChineseauthoritiessaidTuesdaytraceamountsofatmospheric()fromJapanhavebeendetectedinBeijingandmanyareasotherthanHeilongjianginthenortheastbutstressed(强调)theyposenothreattopublichealth.

A.radial 
B.radiate 
C.radiator 
D.radiation