仔细观察下边的漫画（Iraq、Afghanistan、Balkan分别指伊拉克、阿富汗、巴尔干），在冷战结束后屡屡发生漫画中的局面的主要原因是（    ）

【提出问题】催化剂二氧化锰的用量对反应速率是否有影响？

【设计实验】

实验装置如图所示：

实验记录：实验数据如下表：

【实验分析】

    Hello，I'm Danny．This is my day．I get up at seven o'clock every morning. I wash my face and get dressed(穿上衣服)．Then I have breakfast．After that I brush my teeth．I pack my bag and take nay lunch．I like sandwiches．I go to school by bus．I have four classes in the morning．I have lunch at twelve o'clock．Then I have two classes in the afternoon. I go home at half past three．I play with my friends or watch TV．Then I do my homework. I have dinner with my family．I have a shower and brush my teeth．I go to bed at eight o'clock．Busy day is finished．