题目

I was at the store with Mom and baby Lucy. I was looking at the pictures in the pattern(图案)book, trying to decide what to be for Halloween. I wanted to be a fairy princess (公主), but I didn’t get a chance to ask Mom to help me find that page. She was busy. All the women were bent over Lucy’s carrier. Mom wasn’t even looking at me. Lucy started to cry. Mom asked me, “Mary, have you decided yet?” Last year we picked out my costume(流行的服饰) together.      I looked down at the book and saw a picture of a kid in a banana costume. I pointed at the banana. Mom boug右图是某反应的微观示意图，下列说法正确的是 A．反应前后原子种类不变    B．该反应是分解反应    C．反应后的生成物都是氧化物    D．反应的化学方程式为2H2O2      2H2O+O2↑