The Mall of America isn't as big 6 some shopping centres in other countries, but it is a fantastic place to visit with the family.

6. The Mall of America isn't as big as some
shopping centres in other countries, but it is a
fantastic place to visit with the family.

В данном предложении необходимо вставить слово "as", чтобы образовать сравнительную конструкцию "as big as" (такой же большой, как).

Ответ: as