问题 多项选择题

根据环境的不同和探测器的工作原理选择合适的传感器非常重要,应遵循国家标准《火灾自动报警系统设计规范》GB50116-98中的相关规定。一般选型方法为()。

A、对火灾初期有阴燃阶段,产生大量的烟和少量的热,很少或没有火焰辐射的场所,应选择感烟探测器。

B、对火灾发展迅速,可产生大量的热、烟和火焰辐射的场所,可选择感温探测器、感烟探测器、火焰探测器或其组合。

C、对火灾发展迅速,有强烈的火焰辐射和少量烟、热的场所,应选择火焰探测器。

D、对火灾形成特征不可预料的场所,可根据模拟试验的结果选择探测器。

答案

参考答案:A, B, C, D

填空题
阅读理解

For a 400-year-old art form, opera had a bad fame: overweight actresses singing the words which were hard to understand in one of those romance languages you were supposed to learn in high school. And with tickets costing as much as $145 a performance, opera goers also had a certain appearance in people's mind: rich, well-dressed and old.

But now opera companies around the country are loosening their ties and kicking off their shoes in an attempt to keep opera alive and take it to a younger and not so wealthy audience.

Opera producers have found that to attract this crowd, they need to make the opera closer to common people. Because young people don't or won't come to the opera, companies are bringing the opera to them, giving performances in such unusual places as parks, libraries and public schools.

The Houston Grand Opera's choice is the public library, where it performs “mobile operas” shortened versions(剧本) of child-friendly operas. This summer's production is Hansel & Gretel. By performing smaller versions of large productions, producers are able to make people interested while keeping costs at a reasonable level. The San Francisco Opera, which will be celebrating its 75th anniversary this year, is staging Cinderella free of charge, keeping costs down by employing students from its Young Artists' Training Program.

小题1: Which is the main idea of this passage?

A. Opera is famous for its long history.

B. Opera is only performed for rich people.

C. Opera companies are trying to keep opera alive.

D. Young people are not interested in opera.小题2:The underlined phrase in the second paragraph means ______.

A. breaking up the old rules

B. changing the dresses

C. making the audience at ease

D.advertising themselves小题3:Opera companies prefer to perform short versions because ______ .

A. they can be performed in public libraries

B. short versions are easy to perform

C. it is hard to find long versions

D. they can make more people come to opera小题4:The San Francisco Opera employs students in order to ______.

A. celebrate its 75th anniversary

B. reduce the cost

C. attract young people

D. make Cinderella popular