选择合适的单词填空，填序号。 Mary is a little girl. She is only five. She __ 1 __ go to school. She doesn't know how to read 2__ write. But her sister Joan is a school girl. She is ten. She 3 how to read 4 write. One day, Joan sees her little sister in the study. She is at the table. There 5 a pencil in her hand. She is __ 6 something there. ' 7 are you writing, Mary?' she asks. ''I'm writing _ 8 my friend Rose.' 'But how can you do it? You don't know __ 9 to write.'says her sister. 'Well. It doesn't matter. Rose doesn't know how to read, 10 .' (     ) 1. A. don't (     ) 2. A．and (     ) 3. A. know (     ) 4. A．and (     ) 5. A．am (     ) 6. A. write (     ) 7. A. How (     ) 8. A．to (     ) 9. A. what (     ) 10. A. either B. aren't B. or B. knows B. or B. is B. writing B. When B. in B. how B. to C. doesn't C. of C. knowing C. of C. are C. writes C. What C. with C. where C. two