--- How I wish I had studied harder when I was in senior school! --- If you had, you a university student now.
When the party was over, he ______ his friends good-bye and ______.
________ doesn’t seem to have been any difficulty solving the problem.
Joan had often heard ____ said that Marley had no money.
Carl Linnaeus made great contributions to ________ plant species.
He observed a stranger _______ around the store at 12 p.m. last night.