根据题目信息，找到定位信息reading about icehouses；听到定位后，确定But I didn't realise that insulating the blocks with straw or sawdust meant they didn't melt for months为答案句，意思是用稻草和锯屑给这些冰块隔热意味着它们几个月都不会融化。通过对比题目与原文内容发现同义替换kept frozen=didn't melt，得出正确答案B。

根据题目信息，找到定位信息ancient Rome；听到定位后，确定Both the ice and the snow were then sold为答案句，意思是冰块和雪都被卖掉了。通过对比题目与原文内容发现同义替换commercial business=were sold，得出正确答案A。

根据题目信息，找到定位信息modern、worried；听到定位后，确定but of course some people just dump old fridges in the countryside.It's hard to see how they can be stopped unfortunately为答案句，意思是一些人直接把旧冰箱仍在乡下。通过对比题目与原文内容发现同义替换disposed irresponsibly=just dump，得出正确答案B。

根据题目信息，找到定位信息domestic fridges；听到定位后，确定if you divide the cost by the number of years you can use a fridge, they're not expensive compared with some household appliances为答案句，通过对比题目与原文内容发现同义替换good value for money=not expensive，得出正确答案A。