mn giúp em vs ạ:< bài này khó quá

4. You must speak very slowly or he won't be able to understar → Unless ..... 5. Unless he leaves now, he won't catch the last train. → If he .... 6. You will catch a cold unless you keep your feet dry. → If you .... 7. What will happen if he doesn't return? → Supposing ... 8. You can ...