最常见的白内障类型是（）
A.先天性白内障
B.老年性白内障
C.中毒性白内障
D.代谢性白内障
E.放射性白内障
参考答案：B
一组数据15、25、30、18、22、27、19、21的中位数是______．
-- Could you please tell me __________?
-- By learning to forget.
A．what are you doing now
B．how I can deal with the problem
C．when they arrived at the station
D．why was he late for school
