题目

 The born artist devoted all the time he had ______ for something better or different.   A. search                B. searched            C. to search           D. to searching 答案：D如图，BD是⊙O的弦，点C在BD上，以BC为边作等边三角形△ABC，点A在圆内，且AC恰好经过点O，其中BC=12，OA=8，则BD的长为（ ）A．20B．19C．18D．16