2. Исправьте ошибки в предложениях 1. He were at the party. 2. Was they happy? 3. She weren't at school. 4. Were he late? 5. It were a nice day.

Explanation: This exercise focuses on the correct usage of the verb 'to be' (was/were) in the past simple tense. The choice between 'was' and 'were' depends on the subject of the sentence: 'was' is used with singular subjects (I, he, she, it), and 'were' is used with plural subjects (we, you, they) and also with 'you' when it's singular.