问题 单项选择题

对于行波理论,错误的是

A.不同频率的振动均可引起基底膜的行波传播

B.振动频率越低,最大行波振幅越靠近基底膜顶部

C.振动频率越高,最大行波振幅越靠近基底膜底部

D.频率高的声音最大行波振幅发生在蜗孔附近的蜗顶部

答案

参考答案:D

解析:[考点] 人耳对声音频率的分析[分析] 行波理论是人耳对声音频率分析的学说:当声波振动通过听骨链到卵圆窗膜时引起耳蜗内的液体和膜性结构反复移动,形成了振动。振动从基底膜开始作为行波向耳蜗顶部方向传播。不同频率声波引起的行波都是从基底膜的底部开始,但声波频率不同,行波传播的远近和最大振幅出现的部位也不同。声波频率越高,行波传播越近,最大振幅出现的部位越接近卵圆窗处 (即近基底膜底部);相反,声音频率越低,行波传导的距离越远,最大振幅出现的部位越接近基底膜顶部(即蜗孔附近的蜗顶部)。

单项选择题
阅读理解

What is red but green, open but closed and old but new?

The answer is: London’s new double-decker(双层)buses.

Red double-deckers are a symbol of the city. Their status was sealed (确定) in 2008 when one bus made the longer-than-usual trip to Beijing to collect a special passenger: the Olympic Flame.

On November 11, a life-size model of the new bus was shown to the media. The Guardian reported that the new design shares some of the features of the much-missed double-decker Routemaster bus. The original Routemaster was introduced in 1956 but December 2005 saw the end of the old bus’s general service. It was because the bus was difficult for some passengers to use and not environmentally friendly. But it can still be seen on two heritage routes in the city.

Its replacements —boxy, modern double—deckers—have failed to win Londoners’ affection.

London mayor Boris Johnson told the BBC that the new buses were “a combination of nostalgia(怀旧)and the latest technology”. “Standing on the back platform of this bus brings a sense of nostalgia but also shows the best part of the latest technology and design, making this bus fit for the 21st Century,” he said.

The new bus also returns to the driver—and—conductor model—a key feature of the original version. It will be quieter than the old type and have a platform offering passengers the traditional hop—on hop—off service.

The first five new buses will be seen on the roads by early 2012.

小题1:Which of the following shows that red double—deckers are a symbol of London?

A.They have a long history and are seen everywhere in London.

B.They have nothing in common with the traditional Routemaster bus.

C.One such bus went from London to Beijing to collect the Olympic Flame.

D.They carried British athletes from London to attend the Beijing Olympics.小题2:Which of the following is true of the original Routemaster?

A.The bus came into use in the 1960s.

B.The bus was banned because it was harmful to the environment.

C.Passengers didn’t like the bus because it was slow.

D.Visitors to London cannot see such buses on the roads any more.小题3:According to London mayor Boris Johnson, the new Routemaster          .

A.has not been as well received as was expected

B.will be widely used in London in 2012

C.is the most environmentally friendly bus in the UK

D.combines the latest technology with key traditional features小题4:What is the characteristic of the new red double – deckers?

A.The buses will make no noises.

B.The buses will have no conductors.

C.They will be equipped with air – conditioning.

D.The bus platform will offer passengers a traditional service.