函数f（x）=-x4+2x2+3有（ ） A．最大值4，最小值-4 B．最大值4，无

（）一同食用后，会发生不利于人体的生化反应或产生有毒物质，刺激胃肠道而导致腹泻。

A、葱与蜂蜜 

B、葱与红糖水 

C、葱与白糖水 

D、葱与牛奶

阅读理解。

     Zipped into a bag, it looks like a large umbrella. Unfolded, it goes along the street like any other bicycle.

     It's the "A-bike", the brainchild (脑力劳动的产物) of British inventor Sir Cive Sinclair, who made history

in the 1970s hy devel oping the world's first pocket calculator. He described his new invention as "the world's

smallest, lightest foldable bicycle".

     "My original thought was that if you could have a bicycle that was dramatically lighter and more firm than

the ones that exist today, it would change the way in which bicycles are used," said Sinclair.

     The mini-bike showed in Singapore last week and set to go on sale worldwide in 2005 at a price of nearly

US $300, is built for riders as heavy as 112 kilograms and is height-adjustable (可调整高度的). It takes about

20 seconds to fold or unfold.

     Its wheels are a quarter the size of those on a regular bicycle, but Sinclair promises a smooth ride for most

cyclists. "You require no extra energy to ride the A-bike and it can go up to 15 miles per hour (24 kilometers

per hour)," he said. Constructed mainly of plastic, the 5.5-kilogram bicycle folds into a package of less than

0.03 cubic meters (立方米).

     Sinclair also invented the first pocket TV in 1984 and the futuristic C5 electric tricycle in 1985. He said he

hoped the bicycle would attract common citizens, officials, campers or anyone needing transport for a short

trip and he said the next step for the A-bike was to add an electric motor in a few years.

1. The most important character of this kind of bike is its _____.

A. hig size

B. light weight

C. beautiful appearance

D. foldable structure

2. The wheels of a regular bicycle is _____ the size of this kind of bike.

A. four times

B. three times

C. one-fourth

D. one-third

3. This kind of new bike is mainly made of _____.

A. plastic

B. packages

C. bags

D. metal

4. The best title of the text is _____.

A. World's smallest foldable bicycle arriving

B. A new bike a large umbrella

C. A foldable bike, a large bag

D. A great inventor of a new bike

5. This kind of new bike hasn't been fixed with _____.

A. a wheel

B. an electric motor

C. pedal

D. a hand

可以用（）方式重复使用一个已存在的被退化的草图。

A.退化草图

B.退化草图

C.共享草图

D.引用草图

油气的储存方式有哪些？主要是用什么方式？

混凝土搅拌机作业前，应先启动搅拌机（）运转。

A.空载

B.满载

C.半载

D.1/3载