s. having something added to increase the strength
a. 加强的
1. The city was fortified with strong walls to protect it from invaders.
这座城市用坚固的城墙加固，以保护它免受侵略者的攻击。
2. She prefers to eat fortified cereals that provide extra vitamins.
她更喜欢吃提供额外维生素的强化谷物。
3. The army built fortified camps in the mountains for better defense.
军队在山中建立了加固的营地以便于更好地防御。