英语翻译

问题描述:

英语翻译
Luggage space was smaller than average for this class of car--this was compounded by a high boot sill and difficulties in folding the rear seat.
请问高手这句里的high boot sill该怎么翻译呀?长筒靴窗台和车有什么关系呀?

放置行李的空间小于该类型汽车的平均水平——而由于后备厢底框的高度限制,以及折叠后座的困难加剧了这个问题.
觉得这里的high boot still是指后备厢底框的高,应该不是长筒靴的意思.