1. My parents should allow me to study with friends.(改为同义句) I should _________ _________ to study with friends. 2. They often clean their classroom after school. (改为被动语态) Their classroom _________ often _________ by them after school. 3. Li Lei gave Tom a new pen last week. (改为被动语态) A new pen __________ Tom last week. 4. It took him ten years to finish writing the book.(改为同义句) He _________ ten years __________ the book. 5. They will publish these story-books next month.(改为被动语态) These story-books __________ next month.