several group number, then with b ± a, =c,c is is methyl b two vertical box between of accurate size. Per-2~3 measurement, such as proceeds of c values are equal and equal to the design value, then the vertical installation accurate. For example a, b, and c valueswhile on horizontal vertical errors for measurement, General in iron angle code bit at measurement level points grid errors, specific method is from baseline to methyl vertical box center line distance for a,, to b vertical box distance for b, list can measured
1. 计算机的操作系统是一种( ).
2. 批处理系统的主要缺点是( ).
4. 在分时系统中,时间片一定时,( ),响应