Someone must have forgotten to lock the door.

• active

• passive

Your sweater might have been found after we left the restaurant.

• active

• passive

The flight must have been cancelled.

• active

• passive

Dinner at your aunt’s house had to have been good.

• active

• passive

Their ships could have been destroyed in a huge storm.

• not certain

• almost certain

• very certain

They may not have been the first Europeans to visit North America.

• not certain

• almost certain

• very certain

We must not have been invited to the party.

• not certain

• almost certain

• very certain

She must have missed the early train.

• not certain

• almost certain

• very certain

My car / must / steal / very late last night

• My car must have been stolen very late last night.

• My car must have been stole very late last night.

• My car must have been stolen last night very late .

Your daughter / could / drive / to school by her brother

• Your daughter could have been driven to school by her brother.

• Your daughter could have was driven to school by her brother.

• Your daughter, by her brother could have been driven to school.