New Words：
contribute [kən'tribju:t] v. 捐助；捐献；贡献；撰稿；是…的原因之一
Sample Sentences：
Each worker contributed one dollar to the Red Cross.
She contributed a number of articles to the magazine.
It was generous of her to contribute such a large sum.
We contributed a sum of money to the homeless survivors of the earthquake.
generous ['dʒenərəs] adj. 慷慨的, 宽宏大量的, 丰厚的, 丰盛的
survivor [sərˈvaɪvər] n. 幸存者；生还者
New Words：
lung [lʌŋ] n. 肺
cancer ['kænsə] n. 癌；肿瘤；毒瘤
Sample Sentences：
The cancer has spread to his stomach.
Does smoking contribute to lung cancer?
Is there a connection between smoking and lung cancer?
contribution [.kɔntri'bju:ʃən] n. 贡献；捐款；捐赠
connection [kə'nekʃən] n. 连接；关联；联结；接通
New Words：
due [dju:] adj. 由于；因为；到期；应有；应得的
Sample Sentences：
The next train is due in five minutes.
His success is entirely due to hard work.
That money is due to me, but I haven't got it yet.
Have they been paid the money that is due to them?
New Words：
youth [ju:θ] n. 青春；年轻；年轻人；小伙子
Sample Sentences：
His mistake was due to youth and inexperience.
There was a group of youths standing on the street corner.
The youth of today has greater opportunities than ever before.
due [dju:] adj. 由于；因为
New Words：
reasonable ['ri:znəbl] adj.合理的；通情达理的
explanation [.eksplə'neiʃən] n. 解释；说明
Sample Sentences：
My mother was always reasonable.
He gave me a reasonable explanation.
His explanation sounds reasonable to me.
How do you decide what you need and how much is reasonable to pay for it?