Ответ:

1. does my brother work as an engineer? my brother doesn't work as an engineer.
2. do our parents live in the country? our parents do not live in the country.
3. do they work at a plant? they do not work at a plant
4. do my parents buy fruit in this supermarket? my parents do not buy fruit in this supermarket.

Объяснение:

• Вообще-то в (present simple) настоящем простом предложении, главное сказуемое для 3-го лица единственного числа берет окончание -s/-es.
• например: My brother works an engineer. Our parents live in the country.
• B вопросе вспомогательный глагол do/ does переходит в начало предложения, всегда dоеs используется для 3-го лица, единственного числа, с такими как he/she/it. в вопросе главное сказуемое не берет окончаний -s/-es для 3-го лица единственного числа.
• например: does my brother work as an engineer? do our parents live in the country?
• Отрицание образуется с помощью NOT после do/does
• например: my brother does not work as an engineer. our parents do not live in the country.

Ответ:

1. My brother works an engineer.  

(?) Does my brother work...?  

(-)My brother doesn't work...

2. Our parents live in the country.  

(?) Do our parents live...?  

(-) Our parents don't live...

3. They work at a plant.  

(?) Do they work...?  

(-) They don't work...

4. My parents buy fruit in this supermarket.  

(?) Do my parents buy...?  

(-) My parents don't buy...

5. He often goes on business.  

(?) Does he often go...?  

(-) He doesn't often go...