1.sell out 售空
There's often only one of each item in stock at a time, so the pieces can sell out quickly.
这些货架的商品经常都是一次只上一件，所以很快就会卖完K#~t1x=cTG#xZy。

2.get back into shape 恢复身材
I've decided to change my eating habits and get back into shape.
我决定要改变吃东西的习惯，恢复我苗条的身材rc%;FcoUZn5lwiR^@。

3.on average 通常；平均下来
I am out on business trips twice each month on average and one third of a year I am away from home.
我通常每月都要出差两次，一年有三分之一时间在外奔波LcA.8NSOw7t%WV。

4.break down to 分解；
Some rocks from volcanoes break down to form black sand.
有些火山岩被撞碎后会形成黑色的沙HTDT,dylhURzrDi!6ui5。