Keywords. time ball, drop, time signals, tradition.

　　Vocabulary. install, observatory, revive, sweep, viable, hoist,

　　gravity, mechanism, aluminum, flavor, sponsor, Greenwich, Miami, Atlanta.

　　A. Listen to some statements about the time ball, fill in the blankets with what you hear on the tape.

　　The time ball was originally used as a maritime time-keeper.

　　The Greenwich time ball is said to be the world's first public time signal.

　　The ball is automatically raised halfway up the mast at 12:55 pm to the top at 12:58 pm, and drops at 1:00pm.

　　Around 150 public time balls are known or reported to have be installed around the world after that at Greenwich in 1833.

　　The U.S Naval Observatory dropped the first time ball in the United States in 1844.

　　Time balls were used in many cities around the U.S during the 19 century.

　　At the turn of the 20th century, dozens of time balls were being dropped around the world.

　　A few time balls are still ceremonially dropped around the world, ranging from New Zealand to the Old Royal Observatory in Greenwich.

　　B. Listen to a news report about the lowering of the time ball, answer the questions with keywords.

　　In this age of ultra-high technology, many places around the world will mark the start of the new year in an old fashioned way.

　　They will revive an 19th century naval tradition by dropping time balls when 2000 arrives.

　　20 sites on 6 continents will observe a tradition best exemplified by the lowering of lighted time ball in New York city.

　　As the new year sweeps around the world, beginning at the International Date Line, we are going to have the time balls dropping.

　　Steven Dick is a historian at the U.S naval observatory, the institution that maintains the U.S master clock.

　　Everyone is familiar with the time ball in New York's Times Square, but they had a real function in the past.

　　In the 19th century, these were visual time signals which were used to give the time.

　　Mr Dick says the British Navy dropped the first time ball in Portsmouth, England in 1829.

　　The first U.S time ball fell in Washington in 1844.

　　This remained a viable signaling method through much of the 19th century.

　　They were dropped well into the 20th century.

　　At the turn of the century, 100 years ago, there were approximately 2 dozen in the United States that were still in use.

　　Time balls normally fell at noon local time in the United States, and 1:00 pm in Europe, the beginning of the fall marking the exact time.

　　But this year would see them drop at midnight locally.

　　The first time balls, about one and a half meters in diameter, were made of wood and leather and hoisted manually by rope to drop by gravity.

　　Eventually in several instances, electrical motors or mechanisms using water or air pressure were employed.

　　And in some time, materials changed.

　　The Greenwich ball is now aluminum.

　　For this new year, some time balls have local flavor.

　　"Miami will be raising an orange, I understand Atlanta will drop a peach."

　　Steven Dick said San Francisco is to join the event next year, when the U.S naval observatory again sponsors an international time ball drop to signal what he says is the real start of the millennium.

　　C. Now listen to a faster presentation of the material, check your answers.