Решение:
Для выполнения задания необходимо выбрать правильную форму глагола в пассивном залоге прошедшего времени.
- The very first computers 'were invented' about 2500 years ago. (Компьютеры были изобретены, поэтому нужен пассивный залог).
- Simple machines called abacuses were made by the ancient Egyptians. (Абакусы были сделаны).
- These machines ³ were used for thousands of years. A computer was invented nearly 500 years ago by Blaize Pascal but it only was added numbers. (Машины использовались; компьютер был изобретен; числа были добавлены).
- Alan Turing made a different machine 80 years ago. It was done more than any person could do. (Алан Тьюринг сделал машину; она была сделана).
- Then about thirty years ago, the first personal computers were sold. (Компьютеры были проданы).
- Now, of course, they are bought all over the world. (Сейчас их покупают - настоящее время, но в данном контексте возможно использование Present Simple для описания общего факта).
Ответ: 1. were invented; 2. were made; 3. were used, was invented, was added; 4. made, was done; 5. were sold; 6. are bought.