Задание 1. Заполните пропуски соответствующей формой глагола to be (am, is,

Задание 1. Заполните пропуски подходящей формой глагола to be (am, is, are).
1. They _____ engineers.
2. What colour _____ his pen? It _____ blue.
3. Who _____ at the office? We _____.
4. These _____ my books. They _____ on the chair.
5. I _____ not an economist. I _____ a manager.