1、It's single undefended spot is its fleshy, armor-less underside.
它唯一沒有防備的地方是它沒有甲片保護的腹部。

2、The coast was undefended and lay open to attack.
該海岸未設防，易受攻擊。

3、Bombs and poison gas would rain down on undefended cities.
* 毒氣彈紛紛投向那些沒有防御的城市。

undefended翻譯