采用碘量法测定维生素C原料药及其制剂时,所用指示剂应为
A.酚酞指示剂B.结晶紫指示剂C.铬黑T指示剂D.淀粉指示剂E.碘化钾淀粉指示剂
参考答案:D
In most of the schools in China, students can’t __________
A.eat in the classroom
B.listen to music in the hallways
C.play computer games
D.take the mobile phone with them
木材干燥设备装置散热器有()组成。
A、钢管式
B、合金式
C、铝管式
D、肋型暖气管式