呼吸性粉尘是指
A.分散度较大的粉尘B.分散度较小的粉尘C.直径小于15μm的粉尘D.直径小于5μm的粉尘E.能随呼吸进入人体并沉积于呼吸道的粉尘
参考答案:D
— _____ do you surf the Internet, Kate? — Not often, twice a month.
A.How long
B.How old
C.How often
D.How many times
6Kv并联电容器出厂时电极对外壳交流耐压试验电压应为()Kv。
A.3
B.5
C.18
D.25