'back and forth' means that something goes in one direction, then back in the opposite direction. For example, in tennis, the ball goes back and forth.
'back and forth' also means that people are talking and disagreeing, without accomplishing anything. For example, after several weeks of back-and-forth, the U.S. Congress has not agreed on a solution to the debt problem.
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Today, the first Monday in September, is Labour Day (Labor Day in the U.S.), a statutory holiday. Tomorrow is the first day of school.
