1. Вставьте was, were, wasn`t, weren`t 1. My mother … a teacher. 2. We… in Moscow. 3. My friends … at school, but I … at home, because I … well. 4. He… at home with his friends. 5. Tom … at the party, but Liz … . She … busy.

Вот как правильно вставить формы глагола to be в Past Simple:

1. My mother was a teacher.
   — Единственное число (she) → was.

2. We were in Moscow.
   — Множественное число (we) → were.

3. My friends were at school, but I was at home, because I wasn’t well.
   — My friends → множественное число → were;
   — I в прошедшем → was;
   — отрицание «не здоров(а)» → wasn’t.

4. He wasn’t at home with his friends.
   — Единственное число (he) в отрицании → wasn’t.

5. Tom was at the party, but Liz wasn’t. She was busy.
   — Положительная форма для Tom → was;
   — Отрицание для Liz → wasn’t;
   — Утверждение «она была занята» → was.

Общее правило: в прошедшем времени was используется с I/he/she/it, were — с you/we/they; для отрицаний добавляем not → wasn’t/weren’t.