Ответ:

Применим Протокол Е.

1. Определим, какую грамматическую форму требует задание.

В задании требуется преобразовать слово EXTREME в подходящую грамматическую форму, чтобы заполнить пропуск в предложении.

2. Проверим каждую форму на соответствие:

  1. морфологическим требованиям,
  2. орфографическим правилам.

3. Выберем корректную форму: extremely.

Запишем предложение целиком:

In the end she decided not to buy it and I asked her why not. When she went to pay for it, she saw it was extremely expensive and we couldn't afford it.

Ответ: In the end she decided not to buy it and I asked her why not. When she went to pay for it, she saw it was extremely expensive and we couldn't afford it.