题目

如图，正方形中， 、分别是、的中点，若，则（ ）A. 2 B. C. D. 答案：【答案】D【解析】试题分析：取向量作为一组基底，则有，所以又，所以，即.— Did you remember to give Mary the money you owed her? — Yes, I gave it to her ________ I saw her. A．constantly B．directly C．suddenly D．supposedly