政客在演讲时被反对者不断嘲笑打断。

The politician was constantly heckled by opponents during his speech.

heckled 是动词 heckle 的过去分词形式，在句中表示被动。heckle 的意思是"起哄、嘲笑、打断(演讲者)"，通常指在公共场合通过喊叫或提问来干扰演讲者。heckled 在这里表示"被(反对者)嘲笑打断"。