opportunity only knocks once 　　opportunity is like an unexpected stranger passing by. it knocks on someone's door. if the person fails to answer the door, opportunity goes away and knocks on someone else's door. it does not return to the same person.

2013年新東方酷學酷玩冬令營讓學員們感受美語帶給大家無限的游學精彩，一起分享美語短句：

if you can't stand the heat, get out of the kitchen
　　
　　withdraw from an activity if you don't like the conflict and criticism it brings. let other people do it without you.
　　
everyone puts their pants on one leg at a time
　　
　　this is to tell us that we are all equal.
　　
life is a pie
　　
　　it's dished out in large and small pieces and when's gone, it's gone. if we ask for more than our share, we're just begging to be disappointed.
　　
making every minute count
　　
　　doing something productive all the time, not letting any time "slip away."
　　
a pen is mightier than the sword
　　
　　a conflict maybe resolved more deeply and effectively by writing the truth than by resorting to violence.
　　
a new broom sweeps clean
　　
　　a new person in power will change many things and improve the situation. change is better than leaving things as they are.
　　
tomorrow is another day (or, tomorrow is a new day.)
　　
　　no matter how bad things are right now, a person may hope for better prospects in the morning. new opportunities will come.
　　　　
business is business
　　
　　do business with strangers as if they were brothers and with brothers as if they were strangers.
　　
history repeats itself
　　
　　there are patterns in history. nations rise and fall for similar reasons. nations do not change their ways or learn from the mistakes of others. they repeat them.