The best way to explore _______ countryside is on _______foot.
Mr Bush is on time for everything. How _______ it be that he was late for the opening ceremony?
—Are you coming to Alice’s party?—I’m not sure.I _______ go to the concert instead.
—May I smoke here?—If you _______, choose a seat in the smoking section.
—Can we ski on this mountain?—Of course.However, at no time _______ you do so alone.
He _______ have completed his work;otherwise, he wouldn’t be enjoying himself by the seaside.