Task 3. Поставьте нужное отрицание wasn't, weren't, didn't 1. I... at school yesterday. 2. He... read a book last Monday. 3. They ... go to the zoo last summer 4. They ... happy.

Ответ:

• 1. I wasn't at school yesterday.
• 2. He didn't read a book last Monday.
• 3. They didn't go to the zoo last summer.
• 4. They weren't happy.

Объяснение:
1. и 4. Используем 'wasn't'/'weren't' для отрицания глагола 'to be' в прошедшем времени. 'Wasn't' для единственного числа (I), 'weren't' для множественного (They).
2. и 3. Для отрицания в Past Simple с другими глаголами используем вспомогательный глагол 'didn't' и смысловой глагол в начальной форме (read, go).