Mum is cooking lunch. She needs some _____________.[ ]
A. cabbage
B. carrot
C. vegetable
答案:A
实验室有一瓶保管不当的试剂,其残缺的标签如图,这瓶试剂的溶质可能是[ ]
A.单质
B.氧化物
C.碱
D.盐
1.0级的有功电度表应配用不低于0.5级的互感器。( )