关于机械振动和机械波，下列说法中正确的是（ ） A．只要有机械振动，就一定会形成

煤燃烧时产生的热量可以用于发电。光明电厂1月份用含热量为7500大卡/千克的A种煤发电（“大卡/千克”为一种热值单位），2月份改用B种煤发电，A种煤每千克的含热量比B种煤多25%，3月份又改用比较环保的含热量为5000大卡/千克的混合煤发电，这里所说的混合煤是在B种煤中加入含热量为1000大卡/千克的C种煤形成的，这样3月份每发1度电所需B种煤比2月份少0.02千克。1月、2月和3月每发1度电所需要的总热量相同。

（1）求B种煤每千克的含热量；

（2）求该电厂3月份每发1度电所需的B种煤和C种煤各多少千克？

（3）若B种煤的成本为每吨800元，C种煤的成本为每吨200元，若该电厂四月份仍用混合煤发电，且每发一度电所需要的总热量与三月份相同，但要求所消耗的C种煤的数量不低于0.12千克，不超过0.15千克。试求：光明电厂四月份每发一度电所需的燃料成本最少是多少元？最多是多少元？

下图分别是二氧化碳的制取、干燥、收集和检验的装置图。其中错误的是[ ]

A.

B.

C.

D.

Long bus rides are like television shows. They have a beginning, a middle, and an end with commercials thrown in every three or four minutes. The commercials are unavoidable. They happen whether you want them or not. Every couple of minutes a billboard glides by outside the bus window. "Buy Super Clean Toothpaste.” Drink Good Wet Root Beer.” Fill up with Pacific Gas.” Only if you sleep, which is equal to turning the television set off, are you spared the unending cry of "You Need It! Buy It Now!"

The beginning of the ride is comfortable and somewhat exciting, even if you’ve traveled that way before. Usually some things have changed new houses, new buildings, sometimes even a new road. The bus driver has a style of driving and it’s fun to try to figure it out the first hour or so. If the driver is particularly reckless （鲁莽的） or daring, the ride can be as thrilling （惊心动魄的） as a suspense story. Will the driver pass the truck in time? Will the driver move into the rightor the lefthand lane? After a while, of course, the excitement dies down. Sleeping for a while helps pass the middle hours of the ride. Food always makes bus rides more interesting. But you’ve got to be careful of what kind of food you eat. Too much salty food can make you very thirsty between stops.

The end of the ride is somewhat like the beginning. You know it will soon be over and there’s a kind of expectation and excitement in that. The seat of course, has become harder as the hours have passed. By now you’ve sat with your legs crossed, with your hands in your lap, with your hands on the armrests even with your hands crossed behind your head. The end comes just at no more ways to sit.

小题1:According to the passage, what do the passengers usually see when they are on a long bus trip?

A．Buses on the road.

B．Films on television.

C．Advertisements on the billboards.

D．Gas stations.小题2:What is the purpose of this passage?

A．To give the writer’s opinion about long bus trips.

B．To persuade you to take a long bus trip.

C．To explain how bus trips and television shows differ.

D．To describe the billboards along the road.小题3:The writer of this passage would probably favor        .

A．bus drivers who aren’t reckless

B．driving alone

C．a television set on the bus

D．no billboards along the road小题4:The writer feels long bus rides are like TV shows because          .

A．the commercials both on TV shows and on billboards along the road are fun

B．they both have a beginning, a middle, and an end, with commercials in between

C．the drivers are always reckless on TV shows just as they are on buses

D．both traveling and watching TV are not exciting.小题5:The writer thinks that the end of the ride is somewhat like the beginning because both are .

A．exciting

B．comfortable

C．tiring

D．boring

外省客户反映除（）、（）以及骚扰短信、电话问题外，其它类型的投诉建议客户拨回当地省份进行处理，不要进行派单处理。

胡 * * * * 在出席二十国集团领导人金融市场和世界经济峰会上强调：“中国愿继续本着负责任的态度，参与维护国际金融稳定，促进世界经济发展的国际合作，支持国际金融组织根据国际市场变化增加融资能力，加大对受这场金融危机影响的发展中国家的支持。”这是因为（）

A.国家间的共同利益是国家合作的基础

B.维护各国的共同利益是我国对外政策的出发点

C.改善同发展中国家的关系是我国对外政策的基本目标

D.各国家之间的经济发展具有互补性