简述填料函发热的原因？
参考答案：
填料函发热原因：填料函压盖太紧或压偏。轴与填料及压盖径向间隙太小。密封水断水
凝胶电泳（gel electrophoresis）
We cannot （） our offer open for more than three days, so would you please telex your acceptance.
A. have
B. place
C. remain
D. leave
