Teachers recommend parents_____their children under 12 to ride bicycles to school for safety.
As a result of destroying the forests, large ____ of desert ____ covered the land.
The car accident on the main road the other day ____ the careless driving of a driver.
He couldn’t ____ the noise, so he kept the windows shut all day long.
I became more and more excited, trying to work out ____ Mom was taking us on holiday.
____ to reach the headmaster on the phone, the student sent an email instead.