（1）、祈使句（表条件）+ or else/or/otherwise + 主句（表结果）…… “否则……，要不然……”
（2）、祈使句（表条件）+ and +主句（表结果）
[例句]
Hurry up, or you’ll be late for class.
Please call me up before you come, otherwise/or else/or we might be out.
你来之前打个电话，否则，我们也许会出去。
Think it over and you will find the answer.
Give him an inch and he will take a mile. 得寸进尺。
Work hard and you will make progress every day. 好好学习，天天向上。
