2 Do you know exactly how to make your dish? If you do, go to exercise 3. If you don't, do some research. Use a cookbook or go
online. Find a good recipe for your dish.​

The используется, когда говорящий говорит о каком-то конкретном предмете. Например, о ручке, лежащей на столе, которую он видит: The pen at the table.

A и an используются в противоположном случае, а именно, когда говорящий рассказывает не о конкретном предмете. Например, он говорит, что хочет купить машину: I'd like to buy a new car. 

По сути, a и an - это один и тот же артикль, только a используется перед существительным, начинающимся на согласную, а an перед существительным на гласную. Например, an apple, но a dog.

They are from Lviv
1. Are they from Lviv?
2. They are from Lviv, aren't they?
3.They are from Lviv or Kiev?
4. Who are from Lviv?
5. Where they are from?
 My sister is 7
1. Is my sister 7?
2. My sister is 7, isn't she?
3. My sister is 7 or 9?
4. Who is 7?
5. How old is my sister?
It is my pen
1. Is it my pen?
2. It is my pen, isn't it?
3. It is my pen or yours?
7. Whos this pen is?
5. What is it?
My parents are kind
1. Are my parents kind?
2. My parents are kind, aren't they?
3. My parents are kind or angry?
4. Who are kind?
5. What kind of people my parents are?