题目

完型填空 在A、B、C、D四个选项中选出填入空白处的最佳选项 Hello. I'm Tom. I'm a middle school student. It's nice to meet you here. First, let me tell you (1)      about my family. There are five people in my (2)  _   . They are my mother, my father, my sister, my brother and me.   My father is a worker. My mother is an English teacher. My sister is eighteen and my brother is sixteen. I'm fourteen. We (3)   go to the same school. We all enjoy (4)      football games.   My (5)       is at West Street. There is a big tree and some small trees 两个氨基酸缩合成二肽并生成水，这个水分子中的氧原子来自氨基酸的（   ） A．羧基                 B．氨基             C．R基          　D．氨基和羧基