单数句变为复数句在英语中，一个称为单数，两个或两个以上的称为复数，单数句变复数句有以下原则：四变，一去，一留。一、四变1指示代词的变化：this和that分别变为these和those。 如：This is a pen.These are pens.2人称代词的变化：I变we, you还是you, he/she/it变they。 如：I am a student.We are students.3be动词的变化：am或is变为are。4可数名词由单数变为复数，规则如下：一般情况下词尾加s。如bookbooks以s, x, ch, sh结尾的加es。如watchwatches以o结尾的有生命力的加es, 无生命力的加s。 如photophotos, tomatotomatoes(西红柿)以辅音字母加y结尾的，将y变i，再加es。 如familyfamilies以f或fe结尾的，将f或fe变为v，再加es。二、一去：即名词前不定冠词a/an要去掉。如：This is a ruler.These are rulers.三、一留：即原句中的形容词，定冠词the, 副词，介词短语，名词所有格等保留不变。如：This is Toms jacket.These are Toms 写作案例假如你是Kate，下面有两张你的家庭照片，请根据照片写一段介绍，向你的同学介绍一下你的家人。_思路点拨1可用的开头：Hi! Im. I have a big family. There are five people in my family.2教材中出现的主要句型： Here is/are a/two photo(s) of my family. This/That is my. These/Those are my. Whos he/she? He/she is my. Whore they? They are my. My. is/are in the first/next photo.3可用的结尾：I love my family. We are happy.美文欣赏 Hello! My name is Kate. I have a big family. There are five people in my family. Here are two photos of my family. My grandparents are in the first photo. In the next photo are my parents and me. This is my father, and that is my mother, this girl is me. I love my family.