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.

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