But let's get back to the bridges you can actually cross – or drive a tank over. Bridges often play an important role in warfare. An army that attacks across a river may decide to burn the bridge after crossing it. By burning the bridge, the army prevents its enemy from using it. However, the army also destroys its own chance to go back across the river. Burning a bridge leaves the army open to attack.______________________________但是,现在让我们回到那些你真正可以行走,或驾驶坦克能通过的桥梁. 桥梁常常在战争中发挥重要作用. 越过河流进攻的军队可能会决定在通过桥梁后烧毁它.通过烧毁桥梁,军队可以防止其敌人利用它. 然而,军队同时也断了自己的退路.烧毁桥梁让这支军队更易受攻击.___________________________
