Language Hub Advanced, Unit 6.1. Past modals of speculation

Some people say the pyramids must ​ (a)   been built using very advanced technology.

• have
• can
• might
• likely
• could
• must
• may
• had

She ​ (a)   have mentioned it, but I really don't remember.

• might
• couldn't
• must
• can't
• possibility
• had
• mustn't

You ​ (a)   have seen that film - everyone knows it!

• must
• likely
• could
• may
• mustn't
• might
• need

There's a distinct ​ (a)   that the explorer died of some kind of disease.

• possibility
• possible
• might
• must
• may
• had
• possibilities
• abilities

He ​ (a)   have been serious about leaving - he loves it here.

• can't
• might
• must
• may
• had
• couldn't
• could
• can

It's highly ​ (a)   that the bad weather contributed to the accident.

• likely
• might
• must
• may
• had
• couldn't
• could
• can
• possibility
• like

Sandra ​ (a)   to turn back because of the snow on the road.

• may have decided
• might decide
• must had decide
• had deicde
• couldn't decided
• can decided
• likely

He ​ (a)   have phoned me - I've had my phone switched off all morning.

• may well
• might
• must
• may
• had
• can
• possible
• like