Odpowiedź :
1. aren't, are produced
3. wasn't, were installed
3. weren't, is bought
1. Nowadays, most of the products we buy aren't handmade.
They are produced in factories on production lines.
2. The Internet wasn't invented until after World War II.
The first networks were installed in the 1960s and 70s.
3. Home computers weren't sold in large numbers in the 1980s.
Nowadays, however, a computer or a laptop is bought by someone every day!
Pozdrawiam,
Bartek