Past modals of deduction

Sara has lost the hearing in her left ear.

• She may have listened to her music too loud.

• She couldn't have listened to her music too loud.

• She has listened to her music too loud.

His doctor told him he needs to lose some weight.

• He couldn't have had a bad diet.

• He must have had a bad diet.

• He may not have had a bad diet.

Everyone had a terrible stomach ache the day after the wedding.

• It must not have been the food.

• It may have eaten the food.

• It may have been the food.

The antibiotics didn't work.

• His body may have become resistant to antibiotics.

• His body may not have become resistant to antibiotics.

• His body may have resistant to antibiotics.

There was a terrible E. Coli outbreak at the school.

• It may have been the poor hygiene standards.

• It must have been the poor hygiene standards.

• It must have the poor hygiene standards.

The researchers must _______ found the cure. There were at least 20 reporters at the lab.

• had

• have

• may have

This food was rotten. That __________ the reason why most people got sick.

• could have been

• may not have been

• may be

Maybe Darren didn't know about the outbreak.

He ______________ shcool.

• might not attend

• may have attended

• must attend