A:晶体熔点由低到高:CF4<CCl4<CBr4<CI4
B:熔点由高到低:Na>Mg>Al
C:硬度由大到小:金刚石>碳化硅>晶体硅
D:四种气态氢化物按稳定性:SiH4<CH4<H2O<HF
当前,食品安全备受人们关注.下列做法会严重危害人体健康的是( )
— Can you the word “smile”, please?
— Yes, S-M-I-L-E.