This is a necessary consequence of progress.
這是發展的必然后果。
Repairs are necessary to strengthen the bridge.
這座橋需要加固。
A radical overhaul of the tax system is necessary.
有必要徹底改革稅制。
For him, reading was a necessary prelude to sleep.
對他來說，閱讀是入睡的必要前奏。
The alliance stands ready to do what is necessary.
該聯盟已準備好采取必要行動。