听短文,根据短文内容,判断下列句子正误,正确的用“A”表示,不正确的用“B”表示。 短文读两遍。 ( )1. John went to work in a post office before he finished his high school. ( )2. John liked his work. ( )3. John sent letters by driving his car. ( )4. The big dog ran fast to him because he wanted to make John leave. ( )5. The big dog came to pick up the letter for its host. ( )6.The dog was a clerk in a post office. ( )7. The dog was clever.