重点讲解：
1. one another
互相；
eg. The two countries do little trade with one another.
两国之间很少有贸易往来。
eg. We all try and help one another.
我们都尽力互相帮助。
2. as a matter of fact
确切地说；事实上；恰恰相反；
eg. It's not that difficult. As a matter of fact, it's quite easy.
这并不那么困难，实际上，容易得很。
eg. As a matter of fact, I didn't have anything.
事实上，我什么也没有。
3. period of time
时段，一段时间；
eg. The bar was formed by the mud and sand deposited here over a long period of time.
河里的泥沙淤积在这里，年深日久便成了沙洲。
eg. The money was lent for an undefined period of time.
这笔钱无限期借出。

背景资料：
2005年11月16日，在世界影坛被誉为“超级硬汉”的阿诺德·施瓦辛格来到清华大学发表演讲。届年58岁，时任加州州长的施瓦辛格依然风度翩翩，一上场就博得了热烈的掌声。以“执着于你的梦想”为主题，施瓦辛格与学生们畅谈理想，并分享自己的成长故事。他说自己在追逐梦想的过程中，常受到一些人的嘲讽和质疑，但他没有因此动摇，始终坚持通过自己取得的每一点进步去改变生活、改变未来。他的这种“执着于梦想”的精神是否让我们的目标更加坚定呢？

名人经典：
Some of your families maybe don't believe in your dreams. But let me tell you something my young friends. Keep your dreams. No matter what, keep your dreams. Don't give up on them, even when you are temporarily defeated or denied. Keep your dreams.
你们的家人也许不相信你们的梦想，但是，年轻的朋友们，让我告诉你们，执着于你们的梦想！无论如何，坚持你们的梦想。即使你们遭遇暂时的失败或被否定，也不要放弃你们的梦想。执着于你们的梦想。