Заполни пропуски, используй am, is, are. My pen friend ... American. My parents ... teachers. We ... in a big city. My mother ... at work every day.

Am, is, are - это формы глагола to be (быть). Каждая из них употребляется в нужном лице и числе.

Согласно правилу будет так: I am, he/she/it is, you/we/they are.

Используем правило.

My pen friend is American. My parents are teachers. We are in a big city. My mother is at work every day.