题目

—What do you think we can do for our aged parents? —You ________ do anything except to be with them and be yourself. A. don’t have to            B. oughtn’t to           C. mustn’t             D. can’t   答案：A已知两圆的半径分别是2和3，两圆的圆心距是4，则这两个圆的位置关系是（ ）A．外离B．外切C．相交D．内切