besiege|besieged|besieging

这个小镇被持续不断的洪水困扰。

The town was ___besieged by constant floods.

粉丝们不断围堵这位歌星，要求合影签名。

Fans kept ___besieging the singer for photos and autographs.

敌军围困了这座城市长达三周。

The enemy ___besieged the city for three weeks.