本集核心英语单词及例句：

1.crowd (n.)群众,一伙;一堆，许多，大众
She lost her son in the crowd.
她的儿子在人群中走丢了。

2.swarm (n.)蜂群；一大群
A swarm of people encircled the hotel.
一大群人包围了这家酒店。

3.horde (n.)一大群，群；游牧部落
On Monday morning, the horde of people besieged the supermarket.
周一上午，一大堆人将超级市场围了个水泄不通。

4.elbow (n.)肘部；弯头；扶手
He jogged me with his elbow to give me warning.
他用肘轻推我以给我警告。

5.scalper (n.)黄牛（专售戏票等牟利）
We can try to buy some tickets outside the stadium from a scalper.
我们可以试着在体育场外买黄牛票。

6.alternative (adj.)选择性的；交替的
We are very sad to have to do this, but there is no other alternative.
我们为我们不得不这么做而感到难过，但是现在没有其他的选择。

7.sold out 售罄的
The books you ask for all sold out.
你要的书都卖完了。

8.advertisement (n.)广告，宣传
I saw your advertisement on the newspaper.
我在报纸上看见了你们的广告。

9.expense (n.)损失，代价；消费；开支
The expense is unbelievable!
费用太难以置信了！

10.invention (n.)发明；虚构
Oh, this is my invention.
哦，这是我的发明。

11.obstacle (n.)障碍，干扰；妨害物
Form your obstacle into a question and ask colleagues and friends how to overcome it.
把你的障碍当作一个问题，然后去问同事和朋友们如何克服它。