New words：

drift [drift]
v.漂移；漂流；飘；缓缓移动
n.趋势；漂流；趋势

iceberg ['aisbə:g] n. 冰山

Sample Sentences：

Clouds drifted across the sky.
I'm sorry, I got bored and drifted off.
There was a drift of smoke above the trees.
Most of the iceberg is under the water.
The Titanic sank after hitting an iceberg in the early morning hours of April 15, 1912.

New words：

endanger [in'deindʒə] v. 危害；使遭危险；危及
endangered [in'deindʒəd] adj. 濒临灭绝的

Sample Sentences：

You will endanger your health if you smoke.
We should do our best to save endangered species.
The drift of the icebergs in the sea endangers the ships.
That one mistake seriously endangered the future of the company.

iceberg ['aisbə:g] n. 冰山

New words：

species ['spi:ʃi:z] n. 种；物种；种类

Sample Sentences：

There are several species of zebra.
This species of bird now exists only in Africa.
This rare bird has become an endangered species.

endanger [in'deindʒə] v. 危害；使遭危险；危及
endangered [in'deindʒəd] adj. 濒临灭绝的

New words：

humor ['hju:mə] n.幽默
sense of humor 幽默感
humorous ['hju:mərəs] adj. 幽默的；好笑的；诙谐的

humorless ['hju:məlis] adj. 缺乏幽默感的；严肃的
inhumorous [in'hju:mərəs] adj. 不幽默的;不滑稽的

Sample Sentences：

Unlike his brother, he has a good sense of humor.
Humor is one of the greatest gifts our species has been given.

He had a wide mouth and humorous grey eyes.
He was quite humorous, and I liked that about him.

species ['spi:ʃi:z] n. 种；物种；种类

New words：

loose [lu:s]
adj.松的；宽松的；未固定牢的；可分开的
v.松开；释放；放任

Sample Sentences：

She is wearing a loose dress.
Some loose pages fell out of the book.
Never tell him a secret; he's got a loose tongue.
She helped the child loose the laces of his shoes.