题目

Yesterday, Li Mei goes to a store to return a shirt without carrying the receipt(收据)．When she got there，she refused. The salesman said that he wouldn't take it back if she showed him the receipt. Thinking it was no way out，Li Mei put the shirt back in her bag and left. Suddenly two shop guard stopped her and began to search for her. They found the shirt in the bag and looked at it careful.  Many eyes were staring at her, what made Li Mei very embarrassing. Luckily, a salesman came up in time and she was allowed to go.烹制油炸食品时，如果不慎将水滴溅入烧热的油锅中，会听到“叭叭”的响声，同时油花四溅．出现这一现象的主要原因是？（水是热的不良导体，水滴的温度与油的温度不一样，水的沸点比热油的温度低，水的比热容比油的比热容大）