I think you must be mistaken about seeing him at the theatre; I’m sure he_____abroad all week.
Most environmental problems exist because adequate measures for preventing them ____in the past.
—Go for a picnic this weekend, OK? —__________. I love getting close to nature.
__________ Tom didn’t pass the exam made his parents very upset.
She is not certain about __________ she has done anything wrong.
People started to dig in the area for treasure, __________ much damage.