人教版七年级英语上册第七单元第二课时Unit 7 How much are these socks?课件（该课件内含音频文件）

1. I have four pens,  five pencils,  six erasers and twelve  books.  (1～12的基数词无规律) 
2. Thirteen boys and eighteen girls are in the classroom.    (十三到十九,  七个词词尾都有teen) 
3. Twenty and thirty is fifty.  (从二十开始,  整十位数二十到九十,  八个词词尾都有ty) 
4. The trousers are twenty-seven dollars.  (表示几十几的数字,  两词中间加-) 
基数词不难记,  找清规律很容易,  十二以内词各异; 十三数到十九去,  后加teen莫忘记。二十、三十……至九十,  整十之后有ty; 个位到十位,  中间连字符 (-) 别忘记,  十位到百位,  中间and别忘记。