【正文】
They’ ve been back for a year.(改為否定句 ) They _____ _____ back for a year. Answers Ⅰ. 1. have been。 to go 2. has had。 bought 3. haven’t met。 left 4. has been。 is 5. have never visited。 will take Ⅱ . 1. for 2. since 3. since 4. since 5. for Ⅲ. 1. How long has 2. has been 3. don’t。 any longer 4. How often 5. haven’t been