Tom, clean up the broken glass _________ someone walks on it.
All these activities can serve as a platform ______ you might find the one you love.
—How’s your tour around the North Lake? Is it beautiful?—It _______ be, but it is now heavily polluted.
All the other boys have geography books and they will be ahead of me if I don’t get ______.
There is ______ small temple on the island, which can only be reached by ______ water.
—How did you find your visit to the exhibition, John? —______