题目

阅读理解AKFC in North Platte, Nebraska received a letter like on other in their mailboxlast week. Owner Rocky said he was shocked to see someone had written his storeto apologize for stealing chicken! Along with the note were two $1 bills inorder to repay for the chicken this thief took from the buffet(自助餐) line! Wow! Talk about an honest cheat!Therewas no return address on the envelop and Rocky says he wishes he knew who thisfried chicken snatcher (小偷) was! Notso he could catch her and bring her to justice but rather because he'd like togive her some free food! Rocky said, It se下图是学生“对蜡烛及其燃烧的探究”实验操作的示意图，请回答有关问题．（1）如图A所示，将一根火柴梗平放人火焰中，约1秒后取出观察．该实验的目的是______．（2）如图B所示，检验蜡烛燃烧的产物，实验过程中有的同学观察到烧杯底部出现黑色物质．请帮他们分析产生黑色物质的原因是______．（3）如图C所示，用火柴去点燃蜡烛刚熄灭时的白烟．如何操作才能确保实验成功______（只答一点）．