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废弃的平硐必须硐口向里用泥土填实至少5m，再砌封堵。
A
对
B
错
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评标活动应遵循( )的原则。 A．公正 B．公平 C．科学 D．发展 E．择优
在数据库系统中，“事务”是访问数据库并可能更新各种数据项的一个程序执行单元。为了保证数据完整性，要求数据库系统维护事务的原子性、一致性、隔离性和持久性。针对事务的这4种特性，考虑以下的架构设计场景。假设在某一个时刻只有一个活动的事务，为了保证事务的原子性，对于要执行写操作的数据项，数据库系统在磁盘上维护数据库的一个副本，所有的写操作都在数据库副本上执行，而保持原始数据库不变，如果在任一时刻操作不得不中止，系统仅需要删除副本，原数据库没有受到任何影响。这种设计策略称为（1）。事务的一致性要求在没有其他事务并发执行的情况下，事务的执行应该保证数据库的一致性。数据库系统通常采用（2）机制保证单个事务的一致性。事务的隔离性保证操作并发执行后的系统状态与这些操作以某种次序顺序执行（即可串行化执行）后的状态是等价的。两阶段锁协议是实现隔离性的常见方案，该协议（3）。持久性保证一旦事务完成，该事务对数据库所做的所有更新都是永久的，如果事务完成后系统出现故障，则需要通过恢复机制保证事务的持久性。假设在日志中记录所有对数据库的修改操作，将一个事务的所有写操作延迟到事务提交后才执行，则在日志中（4）。当系统发生故障时，如果某个事务已经开始，但没有提交，则该事务应该（5）。空白（2）处应选择（）
理中丸的组成药物中不含有（）。
工业齿轮油可以分为哪几种？
汽轮机调速系统一般由哪些部分组成？
Questions 26 to 30 are based on the following passage. Exercise is one of the few factors with a positive role in long-term maintenance of body weight. Unfortunately, that message has not gotten through to the average American, who would rather try switching to “light” beer and low-calorie bread than increase physical exertion. The Centers for Disease Control, for example, found that fewer than one-fourth of overweight adults who were trying to shed pounds said they were combining exercise with their diet. In rejecting exercise, some people may be discouraged too much by caloric-expenditure charts: for example, one would have to briskly walk three miles just to work off the 275 calories in one delicious Danish pastry (小甜饼). Even exercise professionals concede half a point here. “Exercise by itself is a very tough way to lose weight,” says York Onnen, program director of the President’s Council on Physical Fitness and Sports. Still, exercise’s supporting role in weight reduction is vital. A study at the Boston University Medical Center of overweight police officers and other public employees confirmed that those who dieted without exercise regained almost all their old weight, while those who worked exercise into their daily routine maintained their new weight. If you have been sedentary (极少活动的) and decide to start walking one mile a day, the added exercise could burn an extra 100 calories daily. In a year’s time, assuming no increase in food intake, you could lose ten pounds. By increasing the distance of your walks gradually and making other dietary adjustments, you may lose even more weight. Some people dislike exercise because （）
一个人如果充满积极的、正面的心理特质，他就能消除或减少消极的、负面的心理特质，将有助于形成（）的职业态度。
铝氧率常用（）表示。
脚手架工程费属于建筑安装工程费中的（）。
轴流式风机有什么优缺点？并列时应注意哪些问题？