Put personal pronouns in objective case

1.These are very good exercises. Do (they) at home, please. 2. This engineer works with (I). I know (he) well. 3. Write these words out in your exercise-book please and learn (they). 4. Read this letter and translate (it) into English, please. 5. I know this girl. She works with (we). 6. Take this book and read (it) at home, please. 7. Is he going to speak to (he) about his new work? 8. These are very good exercise books. Where do you get 9. My sister knows English well._​