Most animals have legs now，one dog has four legs，two dogs have eight legs

Eg：T:two dogs，S:eight legs

T:three dogs S：twelve legs

Step3 Dills&practice

1.Show students the PPT，use "there are/is"to describe the pictures[明1]

2.show the crayons：how many crayons are there？let's count（lead in crayon）

show studens the PPT: There are only nineteen crayons，but there are twenty children in the class（此处板书）

Step4 Learn the text

① Watch the cartoon with questions:

Q1：What did Ms Smart buy yesterday？

课件展示动物，并以倍数出现让学生脑中快速闪现十几的英文表达法。