1. He know the answer for question. Does he know the answer for question? He doesn't know the answer of question.2. We understand, it's time to do. Do you understand that it's time to do? You don't understand that it's time to do. 3. I think, it's too late. Do you think it's too late? I don't think it's too late. 4. Interpreters translate many books to English. Do interpreters translate many books to English? Interpreters don't translate many books to English.