1 It’s hard to keep up with my classmates now because they are learning a lot. 2 He ate in the living room. 3 They had been

Пояснение:
The past continuous tense is used to describe an ongoing action or event that happened in the past. It is formed by using the past tense of the verb «to be» (was/were) with the present participle verb form (-ing).

1. «It’s hard to keep up with my classmates now because they are learning a lot.»
— In this sentence, the past continuous tense is used to describe an ongoing action of learning by the classmates. It suggests that the classmates were continuously learning and the speaker found it difficult to keep up with them.

2. «He ate in the living room.»
— Here, the past continuous tense is not used. Instead, the simple past tense is used to describe a completed action of eating in the living room.

3. «They had been waiting for me for two hours.»
— In this sentence, the past continuous tense is used in the form of the past perfect continuous tense. It suggests that the action of waiting started in the past and continued up until a certain point in the past.

4. «I was having a shower when somebody rang the doorbell.»
— Here, the past continuous tense is used to describe an ongoing action of having a shower while another action (ringing the doorbell) happened simultaneously.

5. «It had been such nice weather for the whole week.»
— In this sentence, the past continuous tense is not used. Instead, the past perfect tense is used to describe an action or a condition that happened before a specific point in the past.

6. «We had been living there for a very long time.»
— This sentence uses the past perfect continuous tense to describe an ongoing action of living in a place that started in the past and continued up until a certain point in the past.

7. «We had more than 15 exams and 25 projects in total.»
— In this sentence, the past simple tense is used to describe a completed action in the past. It indicates that the speaker had a certain number of exams and projects in the past.

Дополнительный материал:
Rewrite the following sentence using the past continuous tense:
«I played tennis yesterday afternoon.»
Answer: «I was playing tennis yesterday afternoon.»

Совет:
To better understand and recognize the past continuous tense, it is helpful to practice forming sentences in this tense and contrasting it with the simple past tense. Pay attention to the usage of «was/were» and the «-ing» form of the verb. Reading and listening to stories or dialogues in the past continuous tense can also improve your understanding of how this tense is used in context.

Упражнение:
Rewrite the following sentence using the past perfect continuous tense:
«She had been studying all night.»
Answer: «She had been studying all night.»