题目

—When did your school hold the sports meet?                —Last week. And I _______ the girls’ 400-metre race.               A. joined          B. took part in  C. will join   D. will take part in 答案：B（2014•渭南二模）如图，圆O是△ABC的外接圆，过点C的切线交AB的延长线于点D，CD=2，AB=BC=3．AC的长为 ．