10kV柱上真空负荷开关的（），低压控制回路和操作机构均密封在开关箱体内。

阅读下列材料，完成下列问题。

材料一　“本宪法所授予之立法权，均属于由参议院与众议院组成之合众国国会……众议院以各州人民每2年所选举之议员组成之……行 * * 属于美利坚合众国大总统。大总统之任期为4年，同任副总统之任期亦然，大总统与副总统，应依照下列手续选举之……”

材料二　宪法规定立法权归于由参议院和众议院组成的两院制议会。总统任期7年，是国家元首和军队的最高统帅……经参议院同意有权解散众议院。议会采取两院制，参议院通过间接选举产生，有权否决众议院通过的法律。

材料三　“凡未经议会同意，以国王权威停止法律或停止法律实施之僭越权力，为非法权力。”“未经议会准许，借口国王特权，为国王而征收，或供国王使用而征收金钱，超过议会准许之时限或方式者，皆为非法。”“议会之选举应是自由的。”

材料四　第12条：“皇帝有权召集、召开联邦议会和帝国议会，以及使议会延期或结束。”第15条：“由皇帝任命帝国首相。”

第18条：“（皇帝）有创制法律之权”。

（1）上述四则材料分别出自欧美国家的什么政治文献？

（2）以上材料反映了资本主义国家代议制的哪两种基本类型？

（3）对君主和议会的关系，材料三和材料四的规定有什么不同？

（4）根据上述材料归纳，就大多数国家而言，资产阶级代议制具有哪些特征？

两个质数的积是91，这两个质数是______，两个合数的和是17，这两个合数是______．

在面向对象方法中，类的实例称为【 】。

下列关于关系模式规范化的叙述中，哪一条是正确的？（）

A．若R∈1NF，则必然R∈2NF

B．若R∈2NF，则必然R∈3NF

C．若R∈3NF，则必然R∈4NF

D．若R∈4NF，则必然R∈BCNF

The exploitation of the power in the Sun’s rays is a form of alternative energy now showing new commercial promise.
In the US, manufacturers have made important (26) in the development of the technology to bring down the cost of solar conversion systems (27) improving their reliability.
The direct conversion of solar (28) electrical energy, using photovoltaic cells (29) distinct advantages as an alternative energy option.
(30) other forms of renewable energy, photovoltaic is based on modular solid state devices which can be mass (31) at a relatively low cost.
Here wafers of silicon—not dissimilar (32) ones which are turned into silicon chips— (33) an electric current when light falls upon them.
When built into panels or modules where each cell interconnects, the amount of electricity generated can be large enough to (34) a home or even a community.
Over the past 10 years, (35) extensive research and substantial Government and private industry funding, the price of photovoltaic modules has dropped (36) .
(37) in 1973-74 the price per peak watt was between US $100 and $150, commercial prices for small array system now vary between $6.50 and $7 per watt.
This rapid price reduction has been accompanied by a 400 per cent jump in the (38) efficiency of photovoltaic modules.
(39) solar cells are poor converters of sunlight to electricity. Early cells could only manage to mm about five per cent of the incident rays into electricity, but recent development have increased (40) to more than 10 percent.

A．strides

B．background

C．investments

D．strategy