听力原文
How High Can You Jump?
Flea1) trainers have observed a strange habit of fleas while training them．Fleas are trained by putting them in a cardboard box with a top on it．The fleas will jump up and hit the top of the cardboard box over and over and over again．As you watch them jump and hit the lid，something very interesting becomes obvious．The fleas continue to jump，but they are no longer jumping high enough to hit the top．
When you take off the lid，the fleas continue to jump，but they will not jump out of the box．They won’t jump out because they can’t jump out．Why？The reason is simple．They have conditioned2) themselves to jump just so high．Once they have conditioned them－selves to jump just so high，that’s all they can do．
Many times，people do the same thing．They restrict3) themselves and never reach their potential4)．Just like the fleas，they fail to jump higher，thin king they are doing all they can do．
参考译文
你能跳多高？
跳蚤训练人在训练时发现跳蚤有一个奇怪的习惯。训练时，跳蚤被放在有顶盖的纸板盒里。跳蚤会不断地跳起来，撞击顶盖。你观察它们跳起来撞击顶盖，会慢慢注意到一个有趣的现象。它们仍不断地往上跳，但不会再撞到顶盖。
当你把顶盖拿开时，跳蚤还会接着跳，但不会跳出盒子。它们不会跳出来是因为它们已经跳不出来了。为什么？原因很简单。它们已经习惯于只跳这么高了。而一旦习惯于只跳这么高后，它们就只能跳这么高。
很多时候，人们也是一样。他们自己限制自己，从来不去努力开发自己的潜力。就像跳蚤一样，他们没有能够跳得更高，还以为已经把自己的能力发挥到了极限。
NOTE 注释：
1. flea [fli:] n. 跳蚤, 低廉的旅馆，生蚤的动物
2. condition [kEn5diFEn] vt. 以...为条件, 使达到要求的情况
3. restrict [ris5trikt] vt. 限制, 约束, 限定
4. potential [pE5tenF(E)l] n. 潜能, 潜力, 电压
