题目

The Plains Indians believe in the Great Spirit who has power ______ all things including animals, trees, stones and clouds. A．of          B．at       C．over       D．in 答案：C    解析: 考查介词的用法。over有“超过，高于”的意思。  若m2－n2＝6且m－n＝3，则m＋n＝__________.