Uzupełnij zdania poprawnymi formami strony biernej, tak aby zachować znaczenie zdania wyjściowego.
1 Isaac Newton discovered gravity.
Gravity _______________ by Isaac Newton.

2 Millions of people visit this website every day.
This website _______________ by millions of people every day.

3 They didn’t deliver my new speakers yesterday.
My new speakers _______________ yesterday.

4 We don’t use these devices very often.
These devices _______________ very often.