The crowd was rubbernecking at the accident scene, straining their necks to get a better view of the tragedy.

rubbernecking 是动词 rubberneck 的现在分词形式。rubberneck 由 rubber（橡胶）和 neck（脖子）组成，字面意思是"像橡胶一样伸长脖子"，引申为"伸长脖子好奇地张望"，通常指人们出于好奇而围观事故或异常事件的行为。