It's impossible that he knew the problem ---- HE ............. THE PROBLEM
HE CAN'T HAVE KNOWN THE PROBLEM
We have bought more food than was necessary for the party ---- WE _______ FOR THE PARTY.
WE NEEDN'T HAVE BOUGHT MORE FOOD FOR THE PARTY.
I'm sure they didn't phone you --- THEY __________ YOU.
THEY CAN'T HAVE PHONED YOU.
It's just possible that he went to bed early. ---- HE ________EARLY.
HE MIGHT HAVE GONE TO BED EARLY
When she was ten years old, she had the ability to read people's minds. ----- SHE__________________ PEOPLE'S MINDS WHEN SHE WAS TEN YEARS OLD.
She COULD READ people's minds when she was ten years old.
It was careless of him to go without checking the time. --- HE ____________ THE TIME BEFORE GOING
He SHOULD HAVE CHECKED the time before going.
Perhaps they came up with a better solution last night. (MAY) --- THEY _________ UP WITH A BETTER SOLUTION LAST NIGHT.
They MAY HAVE COME up with a better solution last night.
