Вопрос пользователя:
They__a lot of postcards while their mother came ( buy, buys, have bought, were buying, bought)
Илюха отвечает:
They were buying a lot of postcards while their mother came.
They__a lot of postcards while their mother came ( buy, buys, have bought, were buying, bought)
They were buying a lot of postcards while their mother came.