在所有圆特性的阻抗继电器中，当整定阻抗相同时，（）反映过渡电阻能力最强。 A.全阻抗

左心房与（）相连，并接受回流到心脏的血液。

A、右心房

B、右心室

C、肺静脉

D、左心室

根据《混凝土结构耐久性设计规范》(GB/T50476—2008)规定，结构所处的环境类别分为五类，其中Ⅱ类是指()。

A.一般环境

B.特殊环境

C.冻融环境

D.潮湿环境

Of all the employed workers in the United States, 12.5 million are part of a temporary workforce. The United States Bureau of Labor Statistics counts 9.2 percent of workers as those who have______(1) they term "alternative employment arrangements." The government predicts that temporary staffing agencies______(2) experience growth of 49 percent by 2010. If numbers increase at the rate ______ (3), these companies will add 1.9 million new jobs by 2010. That’’s more than any______(4) industry.Temporary workers were the first ones to be affected by the recent economic recession, but they are______(5) to be the first to regain positions as the economy picks up and companies work to rebuild. Employers use temporary workers as a resource because_______(6) offer flexibility and come at a low cost. Many temporaries are categorized as "independent contractors" instead of employees,______(7) allows the employer to avoid______(8) certain taxes. Because they are not required to offer benefits to temporary workers, companies can save a great deal of money by hiring temps. Usually, temporary workers can qualify_______(9) benefits if they work for a staffing company for a certain length of time. Most temps, however, do not continue with one company long______(10) to qualify for them because they regard the position as a step on the ladder to a______(11) position later.According to Richard Wahlquist, president of the American Staffing Association, 75_______(12) of temporary workers hope for transition out of the temporary staffing category______(13) a period of time. Wahlquist finds that temporary workers spend about 11 weeks on various assignments before their______(14) out of the temporary workforce. Many use temporary positions to gain experience and skills______(15) they move on to better jobs. Wahlquist says that the temp workforce as a whole turns______(16) 400 percent each year.Tom Dilworth, research director at the Employment Policies Institute, explains______(17) some workers like having temporary jobs______(18) it affords them a great deal of elasticity with time and everything. Some temps only have a limited______(19) of time to work and temp agencies can help coordinate jobs to fit their schedules. Other sometimes-employees use temporary jobs to get an______(20) to a company from the inside, to get a foot in the door of a certain business or career._______(21) others take temporary positions in hopes their employers will change them over to permanent positions eventually.Nearly all the industries in the United States use temporary workers.______(22) to Tim Costello, coordinator of the North American Alliance for Fair Employment, the growth of temporary labor threatens______(23) job security of permanent workers who fear replacement, as well as the temps who are more accustomed to turnover. He predicts that there will continue to______(24) a gradual shift from permanent employees to contingent staffing, and that such a_____(25) in workplace demographics will "lead to lower wages, poorer working conditions, and more instability."

科学技术是人类文明不断发展的产物，是物质文明与精神文明的共同结晶。阅读下列材料

材料一：

读图

材料二：

二战期间和战后出现的新兴科学技术

材料二反映了二战后世界科技中心在哪个国家？试分析其形成的原因。

某市一栋综合楼，地下共4层，地上共20层，采用框架剪力墙结构，总建筑面积30万m²，主楼与其裙房之间设有防火墙等防火分隔设施，主楼各层建筑面积均大于1000m²。该综合楼总平面布局及周边民用建筑等相关信息如图1所示。该综合楼地下3、4层均为人防层，其主要使用功能均为普通汽车库、复式汽车库和储存可燃固体的库房；地下2层主要使用功能为展览厅、管理用房及燃气锅炉房、柴油发电机房、变压器室、配电室、消防泵房等设备用房；地下1层主要使用功能为消防控制室、管理用房及商场营业厅。主楼首层主要使用功能为门厅、咖啡厅、自助餐厅、商场营业厅，地上2、3层主要使用功能为儿童游乐厅、展览厅、商场营业厅，地上4～19层主要使用功能为办公室，地上20层主要使用功能为会议厅、多功能厅。裙房1～6层主要使用功能为商场营业厅。该建筑按有关国家工程建设消防技术标准配置了室内外消火栓给水系统、自动喷水灭火系统和火灾自动报警系统等消防设施及器材。

根据以上场景，回答下列问题。

消防水泵的启动方式分为哪几种？