open的过去式是opened。open可作形容词、动词和名词，作形容词时，意为开放的、张开的、展开、开放；作动词时，意为打开、开启；作名词时，意为户外、野外、非秘密、公开。
open的基本释义及用法介绍
1、当open作为形容词时，意为开放的;敞开的;张开的;张着的;展开;开放。
例句：She had left the door wide open .
她把房门敞开着。
He was breathing through his open mouth.
他张着嘴呼吸。
The book lay open on the table.
书摊开在桌子上。
The pass is kept open all the year.
通道一年到头畅通无阻。
The bag burst open and everything fell out.
袋子爆开了，里边的东西都散落出来。
The hall of the old house was open to the sky.
旧房子的门厅是露天的。
2、当open作为动词时，意为开;打开;开启;(使)开;开启(瓶盖、封口等)。
例句：Mr Chen opened the car door for his wife.
陈先生为妻子打开车门。
The door opened and Alan walked in.
门开了，艾伦走了进去。
He opened the letter and read it.
他拆开信读起来。
Open your books at page 25.
把书翻到第25页。
3、当open作为名词时，意为户外;野外;旷野;公开;非秘密。
例句：Children need to play out in the open .
孩子需要在户外玩耍。
Government officials do not want these comments in the open .
政府官员不想公开这些评论。
They intend to bring their complaints out into the open .
他们想把心中的种种不满公开讲出来。
