论述往复式压缩机级间压力低于正常压力的原因及排除方法。
Evaluate the following SQL statements that are issued in the given order： What would be the status of the foreign key EMP_MGR_FK？（） [" It would be automatically enabled and deferred."," It would be automatically enabled and immediate."," It would remain disabled and has to be enabled manually using the ALTER TABLE command."," It would remain disabled and can be enabled only by dropping the foreign key constraint and re-creating it."]
配位数
接地体埋深（接地体上端距地面的距离）宜不小于（）m。在严寒地区，接地体应埋设在冻土层以下。 ["0.2","0.5","0.7","0.9"]
下列犯罪中，可以由单位构成的有（） ["集资诈骗罪","贷款诈骗罪","信用卡诈骗罪","保险诈骗罪"]
如何理解和测算机器设备的功能性贬值？
