最初，人们将金银铸造成为铸币，投入流通，充当()。A.一般等人物 B.金属货币 C.

港口与航道工程施工总承包二级资质企业，经理应具有()以上从事工程管理工作经历或中级以上职称。

A.3年

B.5年

C.8年

D.10年

游乐场中有一种叫“空中飞椅”的设施，其基本装置是将绳子上端固定在转盘的边缘上，绳子下端连接座椅，人坐在座椅上随转盘旋转而在空中飞旋，若将人和座椅看成质点，简化为如图所示的模型，其中P为处于水平面内的转盘，可绕竖直转轴OO′转动，已知绳长为l，质点的质量为m，转盘静止时悬绳与转轴间的距离为d．让转盘由静止逐渐加速转动，经过一段时间后质点与转盘一起做匀逮圆周运动，此时绳与竖直方向的夹角为θ，不计空气阻力及绳重，绳子不可伸长，则质点从静止到做匀速圆周运动的过程中，绳子对质点做的功为（　　）

A．

1

2

mg(d+lsinθ)tanθ+mgl(1-cosθ)

B．

1

2

mgdtanθ+mgl(1-cosθ)

C．

1

2

mg(d+lsinθ)tanθ

D．

1

2mgdtanθ

“If you run for more than five minutes at any time, you might need a pair of running shoes,” advises Stephen Pribut, a US sports medicine expert. Running shoes are highly technical footwear. They provide stability（牢固）while bearing up to three times the wearer’s body weight. But it’s not easy to find the right pair. Finding the right running shoes is something of an art, or a science and a feel.

The science part begins with the shape of the arch（弓）of your foot, which anyone can find out at home with this quick experiment: Put your foot in water and place it on a piece of brown paper. If you see a “C” shape on the paper when you remove your foot, you have a rare high arch. If the shape looks more like a rectangle, that means you have flat feet. See something in between? That’s a normal arch.

Conveniently for shoppers, shoe companies nowadays divide their shoes in three categories: neutral(for high arches), stability(for normal or low arches) and motion control(for flat arches). So you will know which type suits you.

At this point, most people would just grab an appealing shoe and try it on. But professionals would do a few quality-control tests. First, you bend the shoe toe to heel to see where it bends. If it’s not at the forefoot---where the foot actually bends, be afraid. Then you grip both ends and twist in opposite directions. If you can twist it like a towel, it means there’s zero support. Finally, you squeeze(挤)the heel in both directions. A stable heel won’t cave in.

Now you need to check the mold(模子)that shapes the inside of the shoe: whether it’s wide or narrow in the mid-foot, how it sits on the heel and how roomy the toe box is.

It’s wise to hold off until the afternoon to make the shoe purchase, to allow for any swelling(肿胀) that your feet do throughout the day. Toes also decide sizing choice. The rule is you need a finger’s width from your longest toe (whether that’s your big one or not) to the end of the shoe.

小题1:What is the main idea of this passage?

A．Advantages of wearing running shoes fitting you.

B．Ways to get to know about the shape of the arch of your foot.

C．Advice on how to choose the right pair of running shoes.

D．Best time to buy a pair of running shoes.小题2:If the arch of your foot looks like a “C” shape, you have _________.

A．a normal arch

B．a high arch

C．a flat arch

D．a low arch小题3:．The underlined phrase “cave in” most probably means ______.

A．bend

B．stretch

C．shake

D．crash小题4:．Why is the late afternoon the ideal time to go shopping for shoes?

A．We are likely to be more patient in the afternoon.

B．Feet usually become large late in the day.

C．The toes become longer late in the day.

D．The arch of our feet will be in best shape in the afternoon.

社区的自然环境和人文环境在幼儿的成长中，特别是精神的成长中有着特殊的意义，能增强其爱国的情感、对周围环境的了解等，幼儿园充分利用这一点是发挥了（）。

A.社区文化的教育性

B.社区环境的教育性

C.社区资源的文化性

D.社区环境的文化性

钢材随着含碳量的增加，其（）降低。

A.强度

B.硬度

C.塑性

D.刚度