4.Today’s boards are springier still and provide 15 percent more lift than those of the 1960s.
4.现在的跳水板更有弹性，可以比20世纪60年代的提高百分之十五的高度。
4.Aluminium alloys were introduced into the design of springboards. By the 1960s, the enhanced springiness of diving boards made possible dives at the 1-meter height that had only previously been performed at 3 metres.
4.20世纪60年代,铝合金被引入跳板的设计。提高跳板的弹性，使跳水在1 米高度达到以前3米高度的效果成为可能。
2.if military maneuvers become necessary,they should be completely secret.your troops should carry out orders,not understand the battle plans.the less your soldiers know,the more ignorant your enemy remains of your methods.
2如果军事调运变得必要，他们会完全秘密的进行.你的士兵即使不理解战斗计划，也将会履行命令。你的士兵知道的越少， 你的敌人对你的方法就越无所知。
