I need help with this exercise about active voice. Says Change each sentence to the active voice. Use the by phrase as the subject For example:
- Drivers were warned (by the sign) not to exceed 30 mph.
- The sign warned drivers not to exceed 30 mph.
Passengers are allowed (by the airline) to check one bag for free.
__________________________________ one bag for free.
My answer was
The airline allowed passengers to check one bag for free.
However system told me was wrong. Can you please tell me why?