Mary went to the box office at lunch time,but all the tickets had sold out.为什么这里用had sold out 而不是had been sold out
问题描述：
Mary went to the box office at lunch time,but all the tickets had sold out.
为什么这里用had sold out 而不是had been sold out
答
因为 sell out 通常用主动形式表示被动意义。
答
sell out 意思是东西被卖完、货物脱销,主语只能用表示物品的名词充当,在英语里称作主动形式被动意思,类似的例子还有：
Your hair wants cutting.你的头发需要剪一下.（头发被修剪）
My car needs repairing.我的车需要修理.（车被修理）
This fabric washes well.这种织物很耐洗 （织物被洗）
A ship waters before sailing.船在起航前先加水.（船被加上水）
除前两个例子可以用不定式改写为被动语态,这类动词多数不能用被动语态表示:
Your hair wants to be cut.
My car needs to be repaired.