在由河流水能到水电站电能的转变过程中存在着两种损失，即水头损失和机械损失。
参考答案：错
Bill Jones is creating a charitable trust to provide six annual payments of $ 20000 each, beginning next year. How much must Jones set aside now at 10 percent interest compounded annually to meet the required disbursements（）
A. $ 95815.74.
B. $ 87105.21.
C. $169743.42.
速录学习的本质是（）
A、改变大脑突触链接
B、提速
C、改变已有的录入方式
D、提高准确率
