英语里有个教first conditional和second conditional的东西(不知道

first conditional —— 第一条件句，又称真实条件句，主要用于陈述语气，假设的情况可能发生。第一条件句中的动词应该用一般现在时代替一般将来时；用现在完成时代替将来完成时。如：

If Mary goes to the concert, she will bring her brother.

If the weather is fine tomorrow, we shall go to the country.

second conditional —— 第二条件句，又称虚拟条件，是与现在或将来事实相反的条件，条件句中的动词有：现在—— were/did; 将来 —— were to do/should do/ did.如：

If I were you, I would join them in the voluntary work.

If it were to rain tomorrow, we would cancle the outing.