The students expressed their doubts as to the______of the experiment, (necessary)

各国的科学家意识到威胁人类生存环境的那些严峻事实，向人类发出了严重的警告。

Write an essay of about 150 words describing Kaz Tanaka’s experience on August 6,1945.

当他被叫到前面演讲时，他紧张得嘴唇都白了。

我们惊讶地发现衣衫褴褛的老头儿其实是一个百万富翁。

回收利用旧瓶子比生产新瓶子费用更高，但是为了环保，这样做是值得的。

无论是恶劣的天气还是飞涨的物价都没有影响这家餐馆的生意。

People who leave home in the morning slamming doors behind them are likely to be less than those who leave home with a smile. (product)

Children may go on the trip only with the permission of their parents or_________. (guard)

The police arrested the man who was accused of a serious terrorist___. (act)

_____is a strong feeling of love for and pride in one* s own country, (national)