纳氏泵泵体发热的原因（）、（）、（）。
参考答案：循环酸量过少、氯气入泵钱温度和含水量过多、循环酸入泵前温度高
---What do you think of your new English teacher？
--- She was well prepared for her first lesson and left us a good________.
A．expression
B．instruction
C．appearance
D．impression
