The booklet provides all the necessary information about the college.
这本手册提供有关这所大学的所有必要信息。
Some don’t agree that environmental pollution is a necessary consequence of development.
有些人认为环境污染并不是发展的必然结果。
We should help those who are in great need if necessary.
必要的话,我们应该帮助那些非常需要帮助的人。
The army needs men who are willing to fight, when necessary.
军队需要必要时愿意投入战斗的人。