Choose and correct. 选出错误的一项，并改正。

( ) 1. —Thank you.    —You welcome.                             

                   A      B            C        D  

( ) 2. How  much  kites  do you  have?                              

               A       B       C                  D

( ) 3. Look my new crayons.                                             

              A      B    C       D

( ) 4. How  many  pencil do you have?                                

              A        B        C                 D

( ) 5. Who is you?                                                             

              A    B   C

简述产品生命周期说的主要内容。