three years has passed before we knew it know为什么用过去时

three years has passed before we knew it know为什么用过去时 Two years has _____ _____(流逝) before we knew it. Three years went by before I knew it. 翻译three years had pasted before I knew it three years has/have passed Three years has passed since he came to China.中为什么用has It has passed 10 years since we met last time. three years has passed____ he knew this 是before还是when Time passed quickly and three weeks went by ___ we knew it. Time passed quickly and three months went by .we knew it .A. Time passed quickly and three months went by .we knew it . Three years has almost passed.We ____ in our school that we