化学﹣﹣选修一化学与生活

维生素C（Vitamin，Ascorbic Acid）又叫L﹣抗坏血酸，酸性，是一种水溶性维生素，在空气中及高温下易被氧化．碘单质能将其氧化．其结构如图．

某同学的早餐食谱：一杯牛奶、一块面包、一个鸡蛋、一片西瓜．请分析，他体内的哪种消化液对这些食物中的各种营养物质都有消化作用（    ）

等比数列中，，则=

阅读短文，判断正误。

    My name is Amy. Look! This is my study. You can see a desk in it. There is a computer on the desk. You can see a picture of my family on the wall. They are my parents and me. My father is a doctor. He is tall and strong. My mother is a teacher. She is friendly. I'm a student. I'm quiet. I love my family.

左图到右图的变化，反映的本质问题是（    ）