1．They had been trapped (使困住) in the cave for 20 days before rescued.
2．A lot of the plastics that carmakers are using cannot be recycled (回收利用).
3．If there are no natural reserves (保护区), it is likely that more animals will become extinct.
4．She is seeking a substitute(代替者) for the very man whose departure made her cry.
5．The scientist corresponds with colleagues in order to learn about matters relevant (有关的) to her own research.
6．The hijackers threatened (威胁) to kill one passenger every hour if their demands were not met.
7．The murderer was condemned (判处) to death for what he had done.
8．What a coincidence (巧合) that we were in New York at the same time!
9．Some economists strongly advocate (主张) the reform of government ownership of industry.
10．You mustn't sacrifice (牺牲) environmental protection to promote economic growth.
