When a man knows that he will be put into prison if he uses a potentially deadly object to rob or do harm to another person, he will think twice about it.
【正确答案】 D
【答案解析】解析：题干：若一个人知道如果他用可能致死的物体抢劫或伤害他人后将会进监狱，他会三思而后行。deadly致命的，致死的。passive被动的；lifelong终身的；unhappy不幸福的；fatal致命的，关键的。故答案为D。