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梁式桥的主要施工方法有哪些，各施工方法的特点如何？

答案

参考答案：

1）定支架上的施工，在支架上安装模板就地浇注混凝土的方法，一般仅在小跨径桥或交通不便的边缘地区采用。2）悬臂施工法，在已建成的桥墩上，沿桥梁跨径方向对称逐段施工。3）逐孔施工，从桥梁一端开始，采用一套施工设备或一、二孔施工支架逐孔施工，周期循环，直到全部完成。4）施工法，将预制梁体向前顶推出场地然后继续预制下一阶段梁体直至施工完成。5）转体施工法，在河流两岸或适当位置，利用地形或使用简便的支架先将半桥预制完成，之后以桥梁结构本身为转体，使用机械分别将两个半桥转体到桥位轴线上。

单项选择题

"In the long run," as John Maynard Keynes observed, "we are all dead. " True. But can the (1) run be elongated in a way that makes the long run (2) And if so, how, and at what cost People have dreamt of (3) since time immemorial. They have sought it since the first alchemist put an elixir of (4) on the same shopping list as a way to turn lead into gold. They have (5) about it in fiction, from Rider Haggard’s "She" to Frank Herbert’s "Dune". And now, with the growth of (6) knowledge that has marked the past few decades, a few researchers believe it might be within (7) .

To think about the question, it is important to understand why organisms-people (8) -age in the first place. People are like machines: they (9) That much is obvious. However, a machine can always be (10) A good mechanic with a stock of spare parts can keep it going (11) . Eventually, no part of the (12) may remain, but it still carries on, like Lincoln’s famous axe that had three new handles and two new blade.

The question, of course, is whether the machine is worth (13) . It is here that people and nature (14) . Or, to put it slightly (15) , two bits of nature disagree with each other. From the individual’s point of view, (16) is an imperative. You cannot reproduce unless you are alive. A fear of death is a sensible evolved response and, since (17) is a sure way of dying, it is no surprise that people want to stop it in its tracks. Moreover, even the appearance of ageing can be (18) . It (19) the range of potential sexual partners who find you attractive-since it is a sign that you are not going to be (20) all that long to help bring up baby-and thus, again, curbs your reproduction.

13（）

A.replacing

B.repairing

C.buying

D.upgrading
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单项选择题


所给出的图、表、文字或综合性资料均有若干个问题要你回答。你应根据资料提供的信息进行分析、比较、计算和判断处理。
一、根据以下资料，回答101-105题。

2009年年末全市公路里程20670公里；其中，高速公路里程884公里，比上年年末增加107公里。年末城市道路里程6206公里。
公共交通：年末全市公共交通运营线路701条，比上年年末增加22条；其中轨道交通运营线路9条，增加1条。公共交通运营线路长度18498公里，比上年年末增长2.4%；其中轨道交通线路长度228公里，增长14%。公共交通运营车辆2.4万辆，比上年年末增长2.2%；其中轨道交通运营车辆2014辆，增长17.5%。全年公共交通客运总量65.9亿人次，比上年增长11.2%；其中轨道交通14.2亿人次，增长16.9%。
公用事业：全年自来水销售量9.1亿立方米，比上年增长12.3%。其中，生产运营用水1.3亿立方米，增长8.3%；居民家庭用水4.5亿立方米，增长15.4%。
全年地区用电量达到739.1亿千瓦时，比上年增长7.1%。其中生产用电610.4亿千瓦时，增长6.4%；城乡居民生活用电128.8亿千瓦时，增长10.7%。
全年液化石油气供应总量32.2万吨，比上年下降0.9%；天然气供应总量64.5亿立方米，增长15.6%。年末共有燃气家庭用户602.6万户，比上年年末增长2%；其中天然气家庭用户407.1万户，增长3.7%。全市燃气管线达到10970公里，比上年年末增长1.6%。全市集中供热面积4.3亿平方米，比上年增长1.8%。

2009年，该市新增的一条轨道交通的运营线路为( )。

A．25.3公里

B．27公里

C．28公里

D．28.5公里
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