вставьте артикли a,an,the, где они необходимы.

1. This is a good book. Take THE book from the table. Put this book into
THE bookcase.
2. The weath­er is fine today. THE sky is blue. THE sun is shining brightly in THE blue sky.
3. This is A boy. THE boy is at ( )school. He is A pupil. This boy is my brother's friend. He has A cat, but he has no dog. He likes his cat. He gives THE cat
milk every day.
4. Yesterday I received A letter from my friend. THE letter was interesting.
5. We live in A big house. I like THE house very much.

Не перестаю удивляться первому ответчику. И не стыдно такую чушь писать: He has no a dog...слов нет.

1. This is a good book. Take book from the table. Put this book into
the bookcase. 2. the weath­er is fine today. the sky is blue. the sun is
shining brightly in the blue sky. 3. This is a boy. The boy is at the
school. He is a pupil. This boy is my brother's friend. He has
a cat, but he has no a dog. He likes his cat. He gives a cat
milk every day. 4. Yesterday I received a letter from my friend.
The letter was interesting. 5. We live in a big house. I like the house
very much.

1. опр. арт. , опр. арт. 2. опр. арт. , опр. арт. , опр. арт. --3. неопр. арт. , опр. арт. , --неопр. арт. ---- --неопр. арт. ---- неопр. арт. --4. неопр. арт. --опр. арт. 5. неопр. арт. , опр. арт.

Если Вам нужна английская грамматика, советую учебник "Английский для русских в правилах и упражнениях", автор Караванова Н. Б. Там тема артикля рассмотрена до малейших нюансов.
Вообще это лучший учебник по английской грамматике.
Ещё есть сайт: английскийдлярусских. рф Там есть очень много полезного!