如图，某同学将一块三角形玻璃打碎成三块，现要到玻璃店去配一块完全一样的玻璃，那么最省事的办法是（    ）

　63＋9＝72。

短文改错

    During the summer holidays, I thought I should do anything meaningful instead of touring. So I got a job at fast food restaurant and worked there for a cleaner. I worked 7 hours a day for three week. The job was hard and boring and seemed endless, it made me so tired that I nearly left it halfway. Therefore, I stuck to it with determination. Every day I start off for work early in the morning and got to home late in the evening. Finally, I finished the job before the new school term began. Now, I understand that labor means. I consider it a successful experience, which is worth remembered forever.

在“我喜欢的体育项目”调查活动中，小明调查了本班30人，记录结果如下：（其中喜欢打羽毛球的记为A，喜欢打乒乓球的记为B，喜欢踢足球的记为C，喜欢跑步的记为D）

求A的频率．