本集核心英语单词及例句：

1.idiom (n.)成语，习语；土话
The idiom was overworn by greenhill.
在格林希尔这条成语都被用滥了。

2.oxygen (n.)氧气
Carbon dioxide consists of carbon and oxygen
二氧化碳是由碳和氧组成的。

3.sink in 渗入；完全被理解
Wood does not sink in water.
木头在水中不会沉没。

4.stubborn (adj.)顽固的；顽强的
He is really stubborn!
他实在太顽固了！

5.ineffective (adj.)无效的，失效的
They said the drugs were unsafe and ineffective.
他们曾说这些药物不安全，是无效的。

6.blue in the face 气急败坏，精疲力尽；面红耳赤
He argued with the boss until he was blue in the face.
他和老板争得面红耳赤。