收益具有地区外溢性的公 * * 品或部分地区共同受益的公 * * 品适合由( )。
A.中央提供
B.中央与地方联合提供
C.地方提供
D.地方之间联合提供
参考答案:B
惯性制导系统已广泛应用于弹道式导弹工程中,这个系统的重要元件之一是加速度计,加速度计构造原理的示意图如图所示,沿导弹长度方向安装的固定光滑杆上套一质量为m的滑块,滑块两侧分别与劲度系数均为k的弹簧相连;两弹簧的另一端与固定壁相连,滑块原来静止,弹簧处于自然长度,滑块上有指针可通过标尺测出滑块的位移,然后通过控制系统进行制导。设某段时间内导弹沿水平方向运动,指针向左偏离O点的距离为S,则这段时间内导弹的加速度
A.方向向左,大小为
B.方向向右,大小为
C.方向向左,大小为
D.方向向右,大小为
According to traditional Cherokee beliefs, we are part of (1) . We don’t (2) with it and we’re not trying to (3) it. We are a part of the Great Life. And within the Great Life, there are three great Laws of Nature, which tell us how we have to live in (4) with everything else. The First Law of Nature is that you don’t take any life without real (5) . So we shouldn’t (6) needlessly. We believe everything is alive, including animals, plants and (7) . And so to us, taking the life of a plant is just as grave a 8() as taking the life of an animal. The Second Law is that everything we do should (9) the Great Life. And everything we do (10) the Great Life, and everything that (11) within the Great Life affects us. So it’s very important that what we do will not (12) other parts of the Great Life. The Third Law basically is that we don’t (13) where we live. And where we live is not our (14) , small community. It’s this (15) . We don’t pour chemical (16) down the drain because they all wind up in the water. It might seem a little difficult to live by those three laws in this (17) society. But there are still a lot of things that we can do to bring these laws into our lives, such as (18) , using the (19) as little as possible, and (20) gardening.