Не перевести а сделать задание!- you need to go out for a while.Leave a note for your parents.Write- where you are going? when you'll be back, remind then to walk the dog. 

Dear parents! Don't worry about me, I'm fine. As you remember, I should to walk the dog. So if you're reading it now, I'm in the park with Spot. I'll be back very soon :) Xoxo   Дорогие родители! Не волнуйтесь, со мной всё в порядке. Как вы помните, я должна выгулять собаку. Так что если вы читаете это, я в парке со Спотом. Буду очень скоро :) Целую-обнимаю.

Mom, Dad, I promised Bob to give his CDs back to him. I'll be back approximately in 1 hour. And please, walk the dog, as I can't take it with me. Don't forget about it! @name@