对尺寸精度要求较低，而形位精度要求较高的要素，应按（）规定尺寸公差与形位公差。
A.独立原则
B.包容原则
C.最大实体原则
参考答案：A
阅读理解。
The old man is already sixty years old. But he has only fifteen birthdays. How is it? When is his
birthday?
Keys: His birthday is on February 29th. It’s a leap(闰年) year every four years. So he has only
fifteen birthdays.
根据短文内容填空:
1. The old man is _______ years old.
2. He has only ________ birthdays.
3. His birthday is on _______.
4. A leap year happens(发生) every _______ years.
用直流单臂电桥测量电感线圈的直流电阻时，应( )。
A．先按下电源按钮，再按下检流计按钮
B．先按下检流计按钮，再按下电源按钮
C．同时按下电源按钮和检流计按钮
D．随意按下电源按钮和检流计按钮
