过电压的定义:
参考答案:
所谓过电压就是指在供电和用电运行过程中,由于雷击,操作等原因,产生危及电气设备绝缘的电压大幅增高。
单词拼写(已给出首字母或中文意思)。
1. He was ________ (感激的) for all you did.
2. It took him a long time to ________ (恢复) from operation.
3. Apply sunscreen (防晒霜) on your skin 30 minutes before you go ________. (户外)
4. Our workmate has been in danger. We're all c________ about his health.
5. It made her u________ that she didn't do well in the final exam.
6. Could you give me some a_________ on how to learn English?
7. We usually design a s_________ to find out People's opinions on something.
下列各项不是睾酮的生理作用为()
A.促进精子的生成
B.刺激生殖器官的生长
C.促进男性副特征性征的出现
D.腺垂体分泌FSH发挥负反馈作用
E.促进生精细胞的分化