现在时，过去时，将来时;
每个时态包含4个，共12种。
『现在时』
present tense
1、一般现在时
present simple
I have dinner with Ruby every day.
我每天都跟Ruby一起吃晚饭。
2、现在进行时
present continuous
I'm having dinner with Ruby.
我现在在跟Ruby一起吃晚饭。
3、现在完成时
present perfect
I've had dinner with Ruby.
我跟Ruby吃过晚饭。
4、现在完成进行时
present perfect continuous
I've been having dinner with Ruby for the last half hour.
过去的半个小时里我一直在跟Ruby吃晚饭。