America was discovered by Christopher Columbus in 1492.

America were discovered by Christopher Columbus in 1492.

America is discovered by Christopher Columbus in 1492.

America wasn't discovered by Christopher Columbus in 1482.

The cows are milked three time a day

The farmer is milked by his cows three times a day

The cow was milked by the farmer tree times a day

The cows were milked by the farmer three times a day

The dinosaurs are destroyed by an astreroid million years ago

An asteroid was destroyed by the dinosaurs million years ago

The dinosaurs were destroyed by an asteroid million years ago

An asteroid were destroyed by the dinosaurs millions year ago

The customer is served by the waiter

The customer are served by the waiter

The customer is being served by the waiter

The customer was being served by the customer

"Cien años de soledad" is written by Gabriel García Marquéz.

"Cien años de soledad" were written with Gabriel García Marquéz.

"Cien años de soledad" was written by Gabriel García Marquéz.

"Cien años de soledad" was writes by Gabriel García Marquéz.