高程测量时，测区位于半径为10km的范围内时，可以用水平面代替水准面。( )
参考答案：错
电力客户服务的核心是满足客户的需要，其含义是什么？
Compared to European put options on an asset with no cash flows, an American put option: （）
A. will have a higher, lower bound on its price.
B. will have a lower, lower bound on its price.
C. will have the same lower bound on its price.
