甲基红—溴甲酚绿混合指示剂加入硼酸溶液中，溶液应显暗红色。
参考答案：对
口语应用，根据句意填入适当的句子，词组或单词完成对话。
A: Where is Lucy?
B: 1. to English.
A: 2.___________________________?
B: Yes. She has been there once.
A: 3.___________________________?
B: She went there last week.
A: 4.___________________________?
B: She is going to stay there for a month.
A: Do you know 5.___________________________?
B: She'll be back at the end of October.
A．U=vBl，流过固定电阻R的感应电流由b到d
B．U=vBl，流过固定电阻R的感应电流由d到b
C．U=vBl，流过固定电阻R的感应电流由b到d
D．U=vBl，流过固定电阻R的感应电流由d到b
vBl
vBl