题目

She_______ thirty minutes_______ the piano every day.    A. spends; to practise playing        B. spends; practising playing    C. spend; practising to play            D. spend; practise play 答案：B已知等腰直角三角形的重心到它的直角顶点的距离为4cm，那么这个重心到此三角形另外两个顶点的距离都是    cm．