下列关于项目进度计划系统的说法，正确的是______ A．项目进度计划系统应该在项目

分节段施工时，新旧砼接缝表面必须凿毛、清洗，以保证新旧砼结合良好。砼养护要求保温、保湿、防晒养护不少于（）天，尽量减少收缩、温差的影响，以保证砼施工质量。

上海世博会上展示了大量的新材料、新技术，倡导低碳、环保的生活方式，下列说法正确的是 [ ]

A．展馆中使用的LED灯中的二二极管，主要是由超导材料制成的

B．新型液晶电视机的艳丽色彩是由品红、黄、青三种色光混合而成的

C．使用高压锅煮饭效率更高，原因是气压越高水的沸点越低

D．氢氧燃料电池使用过程中，是将化学能转化为电能

阅读理解。

     Andrew Ritchie, inventor of the Brompton folding bicycle, once said that the perfect portable bike would

be "like a magic carpet…You could fold it up and put it into your pocket or handbag". Then he paused:"But

you'll always be limited by the size of the wheels. And so far no one has invented a folding wheel."

     It was a rare-indeed unique-occasion when I was able to put Ritchie right. A 19th-century inventor,

William Henry James Grout, did in fact design a folding wheel. His bike, predictably named the Grout Portable,

had a frame that split into two and a larger wheel that could be separated into four pieces. All the bits fitted

into Grout's Wonderful Bag, a leather case.

     Grout's aim: to solve the problems of carrying a bike on a train. Now doesn't that sound familiar? Grout

intended to find a way of making a bike small enough for train travel: his bike was a huge beast. And importantly,

the design of early bicycles gave him an advantage: in Grout's day, tyres were solid, which made the business

of splitting a wheel into four separate parts relatively simple. You couldn't do the same with a wheel fitted with

a one-piece inflated (充气的) tyre.

     So, in a 21st-century context, is the idea of the folding wheel dead? It is not. A British design engineer,

Duncan Fitzsimons, has developed a wheel that can be squashed into something like a slender ellipse (椭圆).

Throughout, the tyre remains inflated.

     Will the young Fitzsimons's folding wheel make it into production? I haven't the foggiest idea. But his

inventiveness shows two things. First, people have been saying for more than a century that bike design has

reached its limit, except for gradual advances. It's as silly a concept now as it was 100 years ago: there's plenty

still to go for. Second, it is in the field of folding bikes that we are seeing the most interesting inventions. You

can buy a folding bike for less than ￡1,000 that can be knocked down so small that it can be carried on a

plane-minus wheels, of course-as hand baggage.

     Folding wheels would make all manner of things possible. Have we yet got the magic carpet of Andrew

Ritchie's imagination? No. But it's progress.

1. We can infer from Paragraph 1 that the Brompton folding bike _____.

A. was portable

B. had a folding wheel

C. could be put in a pocket

D. looked like a magic carpet

2. We can learn from the text that the wheels of the Grout Portable _____.

A. were difficult to separate

B. could be split into 6 pieces

C. were fitted with solid tyres

D. were hard to carry on a train

3. We can learn from the text that Fitzsimons's invention _____.

A. kept the tyre as a whole piece

B. was made into production soon

C. left little room for improvement

D. changed our views on bag design

4. Which of the following would be the best title for the text?

A. Three folding bike inventors

B. The making of a folding bike

C. Progress in folding bike design

D. Ways of separating a bike wheel

19世纪下半叶以来，随着美学研究的（）运动走向实验主义，作为浓缩着人类审美创造与艺术经验的艺术本身，才开始逐渐走向现当代美学研究的中心。

燃气管道施工时，不应在管道焊缝上开孔，管道开孔边缘与管道焊缝的间隙不应小于( )mm。

A．50

B．100

C．150

D．200