自从某人做了某某事到现在已经有了某某时间。 这是一个强调句,用it is结构,后面嵌套since引导的时间状语从句 it is/has been +时间(如3days 4years....)+since+一句过去式的话 (my mother had a hair cut, I went to the museum). 例句:从奥林匹克运动会在北京举行到现在,已经过了7年了 It has been seven years since the Olympics were held in Beijing.