荧光灯管的亮度约为()。
A.0.3×104cd/㎡
B.0.3×103cd/㎡
C.0.3×102cd/㎡
D.0.3×10cd/㎡
参考答案:A
- What do we need to buy? - _______.
A.Two kilos of tomatoes and two packets of salts
B.Two kilos of tomatoes and two packet of salt
C.Two kiloes of tomatos and two packets of salt
D.Two kilos of tomatoes and two packets of salt
水质标准是什么?其分类如何?