1 一般现在时 主语 + 系动词 标志词有often,usually,always等
要注意“单三”,即he she it
2 现在进行时 主语+be动词 +动词-ing形式 标志词有now,at this time
3 一般过去时 主语+动词过去式 标志词有ago, yesterday, the day before yesterday, last week, just now等
4 过去进行时 主语+ was/were + doing 标志词有at that time等
5 现在完成时 主语+ have/has + done 标志词有recently, lately, since
6 过去完成时 主语+had + done 标志词有before, by the end of last year等
7 一般将来时 主语+ ①am/is/are/going to + do；②will/shall + do.；③be+doing标志词有tomorrow, next day(week, month, year…),soon等
8 过去将来时 主语+①was/were/going to + do；②would/should + do 标志词有the next day等
