| A rapid means of long-distance transportation became
a necessity for the United States as settlement (新拓居地) spread ever farther
westward. The early trains were impractical curiosities, and for a long
time the railroad companies met with troublesome mechanical problems. The most
serious ones were the construction of rails able to bear the load, and the
development of a safe, effective stopping system. Once these were solved, the
railroad was established as the best means of land transportation. By 1860 there
were thousands of miles of railroads crossing the eastern mountain ranges and
reaching westward to the Mississippi. There were also regional southern and
western lines. The high point in railroad building came with the construction of the first transcontinental system. In 1862 Congress authorized two western railroad compani A. American Railroad History B. Settlements Spread Westward C. The Coast-to-Coast Railroad: A Vital Link D. The Importance of Trains in the American Economy [单选题]有语句“var x=0; while(_____) x+=2:"，要使while 循环体执行10 次，空白处的循环判定式应写为：（）
A.x＜10 B.x＜=10 C.x＜20 D.x＜=20 [单选题]13．迁延不愈的营养不良患儿，有时可引起突然死亡的并发症是
A.．低血钙 B.．低血糖 C.．维生素A缺乏 D.．继发感染 E.．低蛋白血症 [填空题]网卡是计算机与（）介质的接口。
[判断题]洗车机温度传感器检测清洗区温度，当温度≤ 2℃时禁止洗车。（ ）
A.正确 B.错误 [单选题]石、混凝土拱圈横向及斜向最大裂缝不超过( )mm。(A 、3、A)[020102]
A.0.2 B.0.3 C.0.1 D.0.4 [简答题]设平面π过点P1（1，2，-1）和点P2（-5，2，7），且平行于y轴，求平面π的方程．
[单项选择]低渗性早期轻度脱水时血清钠水平应低于（）
A. 135mmol/L B. 140mmol/L C. 141mmol/L D. 143mmol/L E. 155mmol/L [单选题]低压架空线路裸导线对步行可达到的山坡(垂直)地面最小垂直距离为（ ）。
A.5.0m B.4.0m C.3.0m D.2.0m [单项选择]财政收入的相对规模是指( )
A. 财政收入与国内生产总值之比 B. 财政收入与居民收入之比 C. 财政收入与财政支出之比 D. 财政收入与企业收入之比 [单选题]原发性胆汁性肝硬化的标志抗体是
A.抗线粒体抗体2型 B.抗肝肾微粒体抗体 C.抗可溶性肝抗原抗体 D.抗核抗体 E.抗平滑肌抗体 [判断题]双重称号即线路名称和位置称号。
A.正确 B.错误 [单选题]SCADA系统调度主站由( )、服务器、通信前置机、操作员工作站、数据文档工作站、UPS、打印机等设备组成
A.互联网 B.局域网 [判断题]因停电焚烧炉联锁停车应立即切断废液废气，连续开鼓风机以降低炉子温度。( )
A.正确 B.错误 [单选题]口服补液盐中加入葡萄糖的主要作用是( )
A.补充电解质 B.降低血清钾浓度 C.使口服补液盐具有一定的渗透压 D.增加肠道对水钠吸收 E.预防酮症酸中毒 [单项选择]按行政区域应建立地方各级红十字会的是（）。
A. 县级以上 B. 市（地）级以上 C. 乡镇以上 我来回答: 提交
|
