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。例如:I’ve seen the film Titanic before.我以前看过《泰坦尼克》这部电影。
几个基本时态标志词:
一、一般现在时:
标志:always, usually, often, sometimes, every week (day, year, month…), once a week, on Sundays,
结构:①be动词;②行为动词
二、一般过去时:
标志:ago, yesterday, the day before yesterday, last week(year, night, month…), in 1989, 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 do
这里列举的都是最基本的,具体题型中还有很多变化。