**Here are some examples of using the word «a» in English:**
1. I need to buy **a** book for my research.
2. She ordered **a** cup of coffee to go with her breakfast.
3. He is wearing **a** new jacket today.
4. We went to **a** restaurant for dinner last night.
5. My sister is studying to become **a** doctor.
6. I saw **a** movie with my friends yesterday.
7. He has **a** cat and **a** dog at home.
8. She wants to buy **a** car for her birthday.
9. We are going to **a** concert this weekend.
10. He is reading **a** newspaper in the park.
The word «a» is used before a singular countable noun when it is introduced for the first time or when it is not specific. It is also used when the noun is indefinite.