Without my glasses, I couldn’t _____ whether that figure on the blackboard was a three or an eight.
Only when your identity has been checked, ___________.
Great as Newton was, many of his ideas _______ today and are being modified by the work of scientists of our time.
Some passengers complain that it usually _________so long to fill in travel insurance documents.
Xi’an is really a fascinating city and we’ve decided to stay for two weeks.
His parents were teachers in that school, _______ lost their lives in order to save their students in the earthquake.