Vi. make the sentences a) interrogative; b) negative. 1. students have to know some facts of the economy in which we live. 2. he had to sit up late with this work. 3. you will have to get up very early tomorrow. 4. he had to come to the office at 5 sharp. 5. she will have to do it once over again. 6. these documents have to be filled in. 7. they had to cover the whole distance on foot. 8. we shall have to speak to him about his participation in the conference