题目

You are not in good health, I think. You could improve your _____ by running every day.     A. position    B. condition     C. situation     D. energy. 答案：B设集合，，则（CRA）∩B=（ ）A．{x|-1≤x≤1}B．{x|-1＜x＜1}C．{-1，1}D．{1}