buy一般是及物动词，后面直接跟宾语。
例句
How long ago did you buy it?
这东西你是多久以前买的？
The curtains were an impulse buy.
这窗帘是一时心血来潮买下的。
We need to buy some new furniture.
我们需要买一些新家具。
Now is a good time to buy a house.
现在买房子正是时候。
They only buy the best.
他们只买最好的。
Try the shoes on before you buy them.
鞋子要先穿上试一试再买。
