侧面部队

例句：

1. 1. The military had to rely on their side-arms for defense.
   军队不得不依靠他们的手枪来防御。
2. 2. The company's main strength lies in its side-units.
   该公司的主要优势在于其子公司。
3. 3. The enemy launched a surprise attack from the flank, which caught us by surprise.
   敌人从侧面发起了突袭，让我们措手不及。