一个完整的程序必须完成三个层次的过程，它们分别是编码、测试和 【12】 。
参考答案：排错或纠错
Mary felt sad over the loss of photos she had shot in Australia, _____ that was a memory she especially
treasured. [ ]
A. as
B. which
C. when
D. where
比例积分控制中比例和积分部分各有什么特点？
