Заполните пропуски артиклями, где это необходимо.My sister is ... student. Her friends are ... students, too. They live in Moscow. They learn ... English. They usually have classes in ... morning. Their classroom is large. ... walls in ... classroom are yellow. Every morning ... students go into ... classroom and sit down at ... tables. They usually do ... lot of exercises and have ... dictations in class. They also often write on ... blackboard. They do ... exercises at ... home, too.

Вот как правильно вставить артикли (покажу сразу весь текст, потом объяснения):

My sister is a student. Her friends are Ø students, too. They live in Moscow. They learn Ø English. They usually have classes in the morning. Their classroom is large. The walls in the classroom are yellow. Every morning the students go into the classroom and sit down at the tables. They usually do a lot of exercises and have Ø dictations in class. They also often write on the blackboard. They do Ø exercises at Ø home, too.

Пояснения коротко:

• a student — ед. число, исчисляемое, профессия/статус → неопределённый артикль a.

• are Ø students — множественное число в общем смысле → артикль не нужен.

• learn Ø English — с названиями языков артикль не употребляется.

• in the morning — устойчиво с артиклем the (время суток в общем режиме дня).

• the walls / the classroom — говорим о конкретной аудитории и её стенах → the.

• the students / the classroom / the tables — конкретные (те самые) студенты, аудитория и столы → the.

• a lot of exercises — устойчивое сочетание требует a.

• have Ø dictations — множественное число в общем смысле → без артикля.

• on the blackboard — конкретная классная доска в этой аудитории → the.

• Ø exercises / at Ø home — множественное число в общем смысле и устойчивое выражение at home → без артикля.