You should never base anything on a theory that _________ impractical in practice.
The poor child was ______ by his grandmother after his parents died.
—John, look at the time. _____ you play the piano at such a late hour? —Oh, sorry.
—Shall I give you a lift as you live so far away? —Thank you. ______.
Going on a trip into _____ space must be quite _____ exciting experience.
character