isnt的过去式

　　One moment he wasn't there, the next he was.

　　他一分钟前还不在那里，一会儿又在了。

　　She wasn't happy with our work and made us start over.

　　她对我们干的'活儿不满意，要我们返工。

　　It wasn't quite as simple as I thought it would be.

　　这事不完全像我想的那么简单。

　　Now look here, it wasn't my fault.

　　喂，那不是我的错！

　　She didn't even call to say she wasn't coming.

　　她甚至没打电话来说一声她不来了。