若a=(1，x），b=（2x，4），a∥b，则x的值是______．

钢架支护是对围岩( )。

A．主动加固
B．被动加固
C．主动支撑
D．被动支撑

中学生不愿把自己的内心世界轻易地像不了解自己的人透露，另一方面，他们又迫切期望别人的理解，希望得到成人帮助或与同年人的倾谈思想。这表现出中学生：（）与（）的矛盾

某多层民用建筑，采用现浇钢筋混凝土框架结构，建筑平面形状为矩形，抗扭刚度较大，属规则框架，抗震等级为二级，梁、柱混凝土强度等级均为C30，平行于该建筑短边方向的边榀框架局部立面，如图1-4-7所示。

在计算地震作用时，假定框架梁KL1上的重力荷载代表值P=180kN，q=25kN／m；由重力荷载代表值产生的梁端（柱边处截面）的弯矩标准值；由地震作用产生的梁端（柱边处截面）的弯矩标准值。试问，梁端最大剪力设计值V（kN），应与下列何项数值最为接近？（）

A.424 

B.465 

C.491 

D.547

( )是指买方只能在期权到期日方能行使权利。

A．看涨期权

B．看跌期权

C．欧式期权

D．美式期权

For centuries people have been fighting over whether governments should allow trade between countries. There have been, and probably always will be, (1) to the argument. Some people argue that just (2) is best for both the country and the world. Others argue that trade with other countries (3) for some people to make a good living. Both sides are at least (4) .
International trade matters a lot. Its effects on (5) are enormous. Imagine a world in which your country (6) at all with other countries. Imagine what kind of job you would be (7) and what goods you could buy or not buy in such a world.
For the United States, for example, start by imagining that it lived without its (8) a year in imported oil, and cut back on its (9) because the remaining domestic oil and other energy sources were (10) . Producers and consumers in other parts of the economy would (11) if they were suddenly stripped of foreign-made goods like CD players and clothing. On the (12) side, suppose that Boeing could sell airplanes, and farmers could sell their crops, (13) the United States, and that U. S. universities could admit only (14) . In each case there are people who gain and people who lose from (15) international trade. In any case, less or more international trade will have (16) on your career as well as your life.
For years, American companies are often faced with the choice of buying (17) , which are expensive, and foreign-made goods, which are cheap. If the company buys American goods, it may (18) taxpayers by failing to keep prices low. But if it buys foreign goods, it may (19) the jobs of American workers. Recently, Congress has passed a law compelling American companies with government contracts to (20) domestic goods and services.

For centuries people have been fighting over whether governments should allow trade between countries. There have been, and probably always will be, (1) to the argument. Some people argue that just (2) is best for both the country and the world. Others argue that trade with other countries (3) for some people to make a good living. Both sides are at least (4) .
International trade matters a lot. Its effects on (5) are enormous. Imagine a world in which your country (6) at all with other countries. Imagine what kind of job you would be (7) and what goods you could buy or not buy in such a world.
For the United States, for example, start by imagining that it lived without its (8) a year in imported oil, and cut back on its (9) because the remaining domestic oil and other energy sources were (10) . Producers and consumers in other parts of the economy would (11) if they were suddenly stripped of foreign-made goods like CD players and clothing. On the (12) side, suppose that Boeing could sell airplanes, and farmers could sell their crops, (13) the United States, and that U. S. universities could admit only (14) . In each case there are people who gain and people who lose from (15) international trade. In any case, less or more international trade will have (16) on your career as well as your life.
For years, American companies are often faced with the choice of buying (17) , which are expensive, and foreign-made goods, which are cheap. If the company buys American goods, it may (18) taxpayers by failing to keep prices low. But if it buys foreign goods, it may (19) the jobs of American workers. Recently, Congress has passed a law compelling American companies with government contracts to (20) domestic goods and services.