10. Вместо пропусков вставьте необходимые по смыслу модальные глаголы «can», «must», «should». 1. Сhemicals ___ be used carefully in the laboratory. 2. You ___ stay out of the laboratory if your teacher is not there. 3. Many of the chemicals ___ be dangerous. 4. All chemicals ___ be treated with care. 5. How ___ you tell that a substance is pure? 6. Dalton`s ideas about atom ___ explain many scientific laws. 7. A substance ___ be recognized by its properties. 8. A question that we ___ answer is how the atoms get electrical charge.