模料配制需要遵循哪些原则？蜡基模料配制有几种方式？

Since the first Earth Day in 1970,American have gotten a lot “greener” toward the environment . “We didn’t know at that time there even was an environment ,let alone that there was a problem with it,” says Bruce Anderson, president of Earth Day USA.

But what began as nothing important in public affairs has grown into a social movement .Business people, political leaders, university professors, and especially millions of grass-roots Americans are taking part in the movement. “The understanding has increased many ,many times,” says Gaylord Nelson, the former  governor from Wisconsin, who thought up the first According to US government reports , emissions (排放)from cars and trucks have dropped from 10.3 million tons a year to 5.5 tons .The number of cities producing CO beyond the standard has been reduced from 40 to 9 .Although serious problems still remain and need to be dealt with , the world is a safer and healthier place .A kind of “Green thinking ” has become part of practices .

Great improvement has been achieved .In 1988 there were only 600 recycling programs ,; today in 1995 there are about 6,600 .Advanced lights ,motors , and building designs have helped save a lot of energy and therefore prevented pollution .

Twenty –five years ago , there were hardly any education programs for environment .Today , it’s hard to find a public school , university , or law school that does not have such a kind of program .” Until we do that , nothing else will change! ” say Bruce Anderson .

小题1:According to Anderson , before 1970, Americans had little idea about ___

A．the social movement

B．recycling techniques

C．environmental problems

D．the importance of Earth Day小题2:Where does the support for environmental protection mainly come from?

A．The grass –roots level

B．The business circle

C．Government officials

D．University professors小题3:What have Americans achieved in environmental protection ?

A．They have cut car emissions to the lowest

B．They have settled their environmental problems

C．They have lowered their CO levels in forty cities.

D．They have reduced pollution through effective measures .小题4:What is especially important for environmental protection according to the last paragraph ?

A．Education

B．Planning

C．Green living

D．CO reduction

血管介入技术包括哪些内容？

系统评价的内容主要包括（）方面

A、系统运行的一般状况

B、系统性能

C、使用效果

D、经济效益

E、社会效益

夜间道路环境对安全行车的主要影响是什么？

A．能见度低、不利于观察道路交通情况

B．路面复杂多变

C．驾驶人体力下降

D．驾驶人易产生冲动、幻觉

下列哪种情况是并行调度______。

A．用户可以一次触发多个事务
B．在DBMS的执行事务队列中可以有多个事务
C．在一个事务执行完之前，另外一个事务又开始执行
D．两个事务同时执行，事务中的每个操作都同时执行、同时推进