New words：

theme [θim] n.主题；主旋律

Sample Sentences：

Stamp collecting was the theme of his talk.
The novel's central theme is war and peace.
The theme park attracts 2.5 million visitors a year.

New words：

revolve [rɪˈvɒlv] v.（使）转动，（使）旋转；环绕，围绕

Sample Sentences：

The fan revolved slowly.
The earth revolves around the sun.
She thinks that the world revolves around her.
Since childhood, her life has revolved around tennis.

New words：

blank [blæŋk]
adj.空白的；空的
n.空格；空白

Sample Sentences：

Suddenly the screen went blank .
Sign your name in the blank space below.
If you can't answer the question, leave a blank.
My mind was a blank and I couldn't remember her name.
Write on one side of the paper and leave the other side blank.

New words：

vouch [vaʊtʃ] v. 担保；保证；确定；断言

Sample Sentences：

Are you willing to vouch for him?
I can't vouch for it that he is in town.
I was in bed with the flu. My wife can vouch for that.

New words：

voucher [ˈvaʊtʃər] n.代金券；票券；代币券

Sample Sentences：

Can I use this voucher to pay the bill?
The vouchers will be used in dining and cinema.