车辆在高速公路行驶时，可以仅凭感觉确认车速。

甲公司采用FOB价格进口一批原材料，于2007年2月1日装船起运，但由于公司事务繁多，公司相关负责人员与2007年2月5日才想起为该批货物订立了保险合同。2007年2月6日甲公司接到通知该批货物已经毁损，于是甲公司向保险公司索赔。经保险公司调查表明，该批货物是在2007年2月4日毁损的。于是保险公司提出保险合同无效，拒绝赔偿。请问该保险合同效力如何

A．无效

B．有效

C．效力待定

D．由人民法院决定

实体完整性规则要求主属性不能取空值，为此，可通过______来保证。

A．定义主关键字

B．用户自定义完整性

C．定义外部键

D．关系系统自动定义

Deflation is an economic theory relating changes in the price levels to changes in the quantity of money. In its developed (1) , it constitutes an analysis of the (2) underlying inflation and deflation. As (3) by the English philosopher John Locke in the 17th century, the Scottish (4) David Hume in the 18th century, and (5) , it was a weapon (6) the mercantilists, who were thought to equate wealth with money. If the (7) of money by a nation merely raised (8) , argued the quantity theorists, then a "favourable" balance of trade, (9) desired by mercantilists, would increase the supply of money but would not in-crease (10) . In the 19th century the quantity theory (11) to the ascendancy of free trade over protectionism. In the 19th and 20th centuries it played a part in the (12) of business cycles and in the theory of foreign (13) rates.

The (14) theory came under attack during the 1930s, (15) monetary expansion seemed ineffective in combating deflation. Economists argued that the levels of investment and government spending were more important than the money supply in determining economic activity.

The tide of opinion (16) again in the 1960s, when experience (17) post-World WarⅡ inflation and new empirical (18) of money and prices— (19) A Monetary History of the United States (1963) by Milton Friedman and Anna Schwartz—restored much of the quantity theory’ s lost prestige. One implication of this theory is that the size of the stock of money must be considered when shaping governmental policies (20) to control prices and maintain full employment.

10（）

A.wage

B.salary

C.wealth

D.pay

下列（）树种种子属于生理休眠，需采取层积催芽法来催芽。

A、红松

B、银杏

C、油松（不是生理休眠）

D、山楂（播种繁殖或扦插繁殖，不是层积催芽）

倒闸操作的基本原则是：停电时先停（）；后停电源侧；先断断路器；后断隔离开关。送电时先送电源侧；后送负荷侧；先合（）；后合断路器。