―I wonder _____ Shanghai is from New York.―It’s about 15 _______ flight.

______ acupuncture developed, the simple “bian stones” were replaced first by stone and pottery needles, and ________ by metal needles

Car control is a topic _________ Beijingers have argued for a long time.

he third time that Li Ming has been to Xi’an , _______

The children went home from the grammar school，their lessons ________ for the day.