试题题干
Fill in the blanks with the words given in brackets. Make changes or add something where necessary.
I
(know) him for quite a long time before you offered to introduce him.
参考答案
试题解析
本题考查时态。句中有两个动作，一个是“认识他”，一个是“主动介绍”。“认识他”发生在“介绍”之前，offered是一般过去式，所以“认识”是过去的过去，所以用过去完成时。