before 时间点是什么时态的标志
before用作连词,常用于过去时、将来时等,意思是“在……之前;还没来得及……就”。用于It+be+时间段+before...句型中,意思是“在……之后才……”。before用作副词,常用完成时。
一、一般现在时
标志always, usually, often, sometimes, every week (day, year, month…), once a week, on Sundays.
二、一般过去时
标志ago, yesterday, the day before yesterday, last week(year, night, month…), just now, at the age of 5, one day, long long ago, once upon a time, etc.
结构①be动词;②行为动词
三、现在进行时
标志now, at this time, these days, etc.
结构am/is/are+doing
四、过去进行时
标志at this time yesterday, at that time或以when引导的谓语动词是一般过去时的时间状语等。
结构was/were+doing
五、现在完成时
标志recently, lately, since…for…,in the past few years, etc.
结构have/has + done
六、过去完成时
标志before,by,the end of last year(term,month)......
结构had done
七、一般将来
标志tomorrow,next day,soon,in a few minutes....
结构1、be going to 2、will/shall do
八、过去将来时
标志the next day,the following month.
结构1、be going to do 2、would /should