P-17:pull up one's socks 重新再做
A:What do you plan to do in holidays?
A:你假期里准备干什么？
B:I'll have to study.
B：我要学习。
A:Why?
A：为什么？
B:I got a very bad school report this thrm. If I don't pull up my socks. I'll be lagged behind by the class.
B:我这学期的成绩很差，如果再不努力，就跟不上大家了。
