三极管的输出特性曲线随温度升高而上移，且间距随温度升高而减小。
查看答案
NPN型三极管的发射极和集电极都是由N型半导体构成的，所以实际使用时两个电极可以互换。
A. 对
B. 错
【单选题】To make a good preparation for your presentation, the first step you should do is to ____________.
A. learn about your subject matter
B. learn about your audience
C. develop a theme
D. prepare your script
【单选题】Which of the following statements on stage fright is NOT true? _________
A. Stage fright happens to us anytime we start to get nervous at the idea of being in front of an audience.
B. Stage fright is an abnormal phenomenon.
C. Most experienced speakers have stage fright before taking the floor.
D. Most experienced speakers’ stage fright s a healthy sign that they are getting “over-excited” for a good effort.
【单选题】The saying “more haste, less speed” tells us to _______ to allow ourselves time to get into a comfortable pace at the beginning of a presentation.
A. stay calm and start slowly
B. start quickly and talk fast
C. think positively
D. focus on the materials
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