排污泵声音异常，振动大的原因及处理？

已知样本：

15  11  13  15  17  19  15  18  20  19

16  14  15  17  16  12  14  15  16  18

若取组距为2，列频率分布表，则16.5～18.5这一小组的频率为______．

通货膨胀对经济的影响有( )。

A．改变了原有收入和财富占有的比例

B．使投资项目的吸收力下降

C．国际市场需求不足

D．使实际利率上升

Americans like to travel on their yearly holiday. Today, more and more travelers in the United States are spending nights at small houses or inns(客栈)instead of hotels. They get a room for the night and the breakfast the next morning.

Rooms for the night in private(私人的)homes with breakfast have been popular with travelers in Europe for many years. In the past five to ten years, these bed-and-breakfast places have become popular in the United States. Many of these America’s bed-and-breakfast inns have only a few rooms; others are much larger. Some inns do not provide telephones or televisions in the rooms, others do.

Staying at a bed-and-breakfast inn is much different from staying at a hotel. Usually the cost is much less. Staying at an inn is almost like visiting someone’s home. The owners are glad to tell about the areas and the interesting places to visit. Many vacationers say that they enjoy the chance to meet local families.

小题1:Americans take a holiday trip_________.

A．all the year round

B．for years

C．every year

D．every other year小题2:According to the passage, which of the following is NOT true?

A．Some Americans like to stay at bed-and-breakfast homes instead of at hotels.

B．The bed-and-breakfast inns are private homes open to vacationers.

C．The bed-and-breakfast inns have been popular in America for a long time.

D．The bed-and-breakfast inn owners provide a morning meal for their visitors and a room for the night.小题3:Staying at the bed-and-breakfast inns, __________.

A．the travelers needn’t pay anything

B．the travelers don’t have to pay for the telephone or television

C．the travelers can meet and talk with the local people

D．the owners will show the travelers around the area小题4:Which is TRUE according to the passage?

A．European and American vacationers like staying at bed-and-breakfast inns.

B．All Americans enjoy traveling.

C．These bed-and-breakfast inns are all old historic buildings.

D．Staying at a bed-and-breakfast inn is just like at the traveler’s home.

“知识经济”正以飓风的速度和威力裹挟着我们奔向新世纪．我们怎样思考这一问题呢这里可以提供生活中的一个例子．当年，电冰箱出现时，家庭主妇和家庭成员都为之兴奋，在炎热的夏天，一边喝着清凉的饮料，一边在海边的沙滩上晒太阳．没有多久，他们发现皮炎增加，人们在尽情地享受使用电冰箱的乐趣时，并没有哪个人把皮炎和电冰箱联系起来．随着基础研究工作的深入，在南极上空发现了巨大的臭氧层空洞，臭氧的减少，导致紫外光的增多，紫外光灼伤了皮肤，引起了皮炎．在发现含氟氯的烃类化合物是造成这一结果的凶手的同时，人们自然想到了电冰箱，是科学和知识把这两个看来不相干的问题联系起来了．由于这一问题涉及全人类，因此，全社会行动起来，又是立法，又是定条文，着手解决这一问题．最厉害的杀手锏是到某时间限制含氟氯烃的电冰箱进入市场，这就刺激人们去开发氟氯烃的替代物．于是，仅用了3至5年时间，替代物像雨后春笋一样冒了出来，各种无氟、无氯的电冰箱相继问世，人们又有了自由选择的余地．众多的品牌使消费者产生了新的困惑，怎样选择一个能真正表达自己保护环境志向的品牌呢于是，应运而生，就出现了第三方面的认证服务：发一个绿色标志，在产品上一贴，消费者不费力就可以判断哪个品牌符合环保要求．这就又形成了一个市场，即咨询服务市场．①剖析这个小例子，不难发现，知识在其中起到“红娘"的作用．②在上面这个小例子中所涉及的知识是多方面的，有软科学、硬技术，涉及到基础科学研究、法学研究、国际贸易、化学合成、轻工制造、咨询服务等学科和行业．⑧我们还不难发现，所以出现上述这些需要研究的领域，说到底是因为环境保护的需要．④科学的发展使人们更清醒地检讨过去的事情，有些当时可能是合理的，但现在从保护环境的角度，用持续发展的观点去衡量就可能是不可取的．⑤随着科学技术的发展，这种事情可能愈来愈多，这大概就是人们常说的“环境保护的挑战”．⑥既然有需求就能刺激市场，有了市场就有经济的发展，难怪发达国家、自由市场经济国家如此重视“知识经济”．

第二自然段说“于是，应运而生，就出现了第三个方面的认证服务”，那么第一、第二方面是_________．

A．生产立法

B．开发生产

C．开发销售

D．研究销售

如果用反循环压井时环空内有气体，环空内液体流速必须（）气体滑脱速度。

A、大于

B、小于

C、等于