24. The Niagara Waterfalls, ______ is shaped like a semicircle, are 670meters wide, and fall 56 meters in an awesome white sheet of water.
—Can I go to the cinema with you, Daddy? —Sorry, my darling, but the film is _________ for adults only.
Much to ________ surprise of the students, the concert which was held once a year turned out to be ________ complete failure.
Scientists say it may be five or six years _______ it is possible to test this medicine on human patients.
He has the habit of ________ useful information while reading.
He left Wenzhou for Beijing last year, and we ________ him ever since.