题目

. As a considerate teacher, he or she must be good at ______ the students’ mind , seeking for the best way to help them with their problems.    A. reading           B.seeing            C. watching           D. realising 答案：A下列多项式中，不能用完全平方公式分解因式的是（　　）A．m+1+m24B．-x2+2xy-y2C．-a2+14ab+49b2D．n29-23n+1