电阻点焊的电流调大时，会产生（）现象。
A．飞溅变多、焊点颜色变深
B．飞溅变少、焊点颜色变深
C．飞溅变多、焊点颜色变浅
参考答案：A
根据句意及首字母的提示，补全单词。
1. He is no longer b_____ of the class. He has become a top student.
2. Finally, he passed the f_____ exam.
3. He needs to make money to s____ his family.
4. The_____ thing that happened this week is that I didn't pass the exam.
5. I have the a_____ to do the work.
国际“人与生物圈计划”始于（）。
A．1971年
B．1973年
C．1975年
D．1978年
