build up a defense的用法和樣例：
例句
- The first line of defense against disaster is a backup of the data.
備份的數據是應對災難的第一道防線。 - They are the first line of defense in difficult battle conditions, and the AUTOBOTS will fight to the end to keep them out of the hands of MEGATRON.
他們在惡劣環境的戰鬥中是第一道防線，汽車人將為了不讓他們落入威震天的魔爪而戰鬥到底。
