标幺制有什么好处？
参考答案：易于比较电力系统各元件的特性及参数，能够简化计算公式，能在一定程度上简化计算工作。
体育教师应具有哪些职责？
In just three years, the Net has gone from a playground for the local people to a vast communications and trading center where millions swap information or do deals around the world.()
A. business
B. shopping
C. chatting
D. meeting
