build up a defense

• 筑起一道防线

build up a defense的用法和样例：

例句

1. The first line of defense against disaster is a backup of the data.
   备份的数据是应对灾难的第一道防线。
2. 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.
   他们在恶劣环境的战斗中是第一道防线，汽车人将为了不让他们落入威震天的魔爪而战斗到底。