根据以下资料，回答13~16题。 Some young soldiers who had recently joined the army were being trained in modern ways of fighting, and one of the things they were shown was how an unarmed man could trick an armed enemy and take his weapon away from him．First one of their two instructors took a knife away from the other, using only his bare hands and then he took a rifle away from him in the same way．After the lesson, and before they went on to train the young soldiers to do these things themselves, the two instructors asked them a number of questions to see how well they had understood what they had been shown．One of the questions was this: “Well, you now know what an unarmed man can do against a man with a rifle．Imagine that you are guarding a bridge at night, and that you have a rifle．Suddenly you see an unarmed enemy soldier coming towards you．What will you do?” The young soldier who had to answer this question thought carefully for a few seconds before he answered, and then said, “Well, after what I have just seen, I think that the first thing I would do would be to get rid of my rifle as quickly as I could, so that the unarmed enemy couldn't take it from me and kill me with it!” The instructors were teaching the soldiers __.