(4分)下列物质中①澄清石灰水 ②白酒③蒸馏水 ④液氧 ⑤二氧化锰 ⑥过氧化氢溶

已知圆的半径为2，圆心在x轴的正半轴上，且与y轴相切，则圆的方程是（　　）

A．x²+y²-4x=0

B．x²+y²+4x=0

C．x²+y²-2x-3=0

D．x²+y²+2x-3=0

阅读短文，根据其内容回答问题。

Phys ed (physical education) is making a comeback, but with a difference. The new way is to teach skills that are useful beyond gym class, like lifting weights, balancing their diets and building physical endurance（耐力）.

Considering that 15% of American children 6 to 18 are overweight, supporters say more money and thought must be put into phys ed curriculum. In many cases, that may mean not just replacing the old gym-class model with fitness programs but also starting up phys ed programs because school boards（教育委员会）often “cut P.E. completely or decrease（减少）its teachers or the days it is offered,” says Alicia Moag-Stahlberg, the director of Action for Health Kids. The difference in phys ed programs is its short of a national standard.

The wisdom of the new idea has some scientific support. Researchers at the University of Wisconsin have showed how successful the fit-for-life model of gym class can be. They observed how 50 overweight children lost more weight when they cycled and skied cross-country than when they played sports. The researchers have also found that teaching group sports like football results in less overall（全体的）movement, partly because the students who are unwilling to do may sit on the bench.

Another problem with simply teaching group sports in gym class is that only a small part of students continue playing them after finishing their high school. The new method teaches skills that translate to adulthood, which means kids are given skills and experiences so they can lead a physically active life in their future.

小题1:Is the new Phys ed program different from the one before?

小题2:What does the new P.E. program teach the students?

小题3:According to the passage, what do some school boards do with P.E?

小题4:What are the problems with simply teaching group sports?

小题5:What’s the passage mainly about?

某废水处理站工艺流程图如下：

产生固体废物的抹污节点有（）。

A.均质池

B.初沉池

C.曝气池

D.二沉池

女权主义运动先后经历了两次浪潮，第一次浪潮始于（）

A、19世纪60年代

B、19世纪50年代

C、19世纪40年代