52. Don't tell lies to your boss or you'Il be fired at once.
=> If you tell lies to your boss ,you'Il be fired at once.
53. She got married at such an early age: otherwise, she would be at university now.
=> Had she not got  married at such an early age, she would be at university now.
54. I think your mother shouldn't let you use motorbike so early.
=> If I were  your mother , I wouldn't let you use motorbike so early.
55. If it hadn't been for the darkness, I wouldn't have had an accident last night.
=> But for the darkness, I wouldn't have had an accident last night.
57. You must tell me the whole truth or I won't help you.
=> Unless you tell me the whole truth ,I won't help you.
58. The car breaks down so often because you don't take good care of it.
=> Were I you , I would take good care of the car .