besiegment

例句：

1. 1.The army was besieged by the enemy for three weeks.
   军队被敌人围困了三周。
2. 2.The city was besieged by a large group of refugees.
   这座城市被一大群难民包围。
3. 3. The castle was besieged by an army of invaders.
   城堡被一支入侵的军队包围。