钢筋混凝土受压短柱在持续不变的轴向压力N的作用下，经一段时间后，量测钢筋和混凝土的应力情况，会发现与加载时相比，不对的有()

单项选择题A business can do the following in a customer community except ______. ( )A.marketing products B.asking for feedback C.addressing customer complaints D.collecting customers’ private information

多项选择题用锤击沉桩时，为防止桩受冲击应力过大而损坏，不对的有()