1. Hurry up or she will miss the train.
 If __she doesn’t hurry up,she will miss the train. ______________________________________________________________
 If __she hurries up, she won't miss the train. ______________________________________________________________
2. Work hard and he will pass the exam.
 If __he works hard ,he will pass the exam ______________________________________________________________
3. Study hard or you’ll fail in the entrance examination.
 If ___you don’t study hard, you will fail in the entrance exam. _____________________________________________________________
 If ___you study hard, you won't _fail in the entrance exam. ____________________________________________________________
4. With luck, he may pass the entrance examination.
 If __he is lucky, he may pass the entrance examination. ______________________________________________________________
5. You must concentrate, or you won’t understand the lesson.
 If _you don't concentrate,  you will not understand the lesson. _______________________________________________________________
 If __you concentrate, you will understand the lesson.  _____________________