美国经济学家唐帕尔伯格曾说：“他正引导我们走向一个丰衣足食的世界”。指的是（     ）

某校化学实验室有足量氯酸钾、过氧化氢溶液和很少量高锰酸钾．现需要用这些药品制取多瓶氧气．

    Hi, I'm Brian. This is the photo of my family. My grandfather is wearing(戴着) glasses. He has little hair. The one next to him is my uncle. He is wearing a cap. My grandmother has gray hair. She is a kind woman. She is holding(抱着) my younger brother. He has short hair. The woman standing behind me is my mom. She has brown hair. There is a little girl sitting on the table. Her name is Cathy. She is my sister. She is wearing a green T-shirt and a pair of green socks. It's her favorite color. Which one is my father? Well, he is wearing glasses, too. He is in brown shorts and brown shoes. His name is Sam. Now, do you know where he is?