本集核心英语单词及例句：

1.slang (n.)俚语；行话
It was not always easy to understand what American people were telling me, especially when they used slang.
理解美国人说的话并不总是一件容易的事情，尤其是他们用俚语的时候。

2.wrinkle (n.)皱纹
At 91, he is impeccably dressed, with a face as wrinkle-free as his well-ironed shirt.
虽然已是91岁高龄，但他的衣着无可挑剔，脸上就像他精心熨烫的衬衣一样，看不到一丝皱纹。

3.library (n.)图书馆；藏书室；文库
He is in the classroom or in the library.
他不是在教室，就是在图书馆。

4.practice (n.)练习；实习；实行
Practice is the sole criterion of truth.
实践是检验真理的唯一标准。

5.communicate (v.)通讯，交流
We learn a language in order to communicate.
我们学习一种语言是为了交流。