The most important use of drifting bottles is to find ocean currents. When the position and direction of currents are known, ships can use the forward movement of a current or stay away from currents that would carry them off their course. Benjamin Franklin was one of the first to use bottles in the study of currents. He wondered why British mall ships needed a week or two longer than U.S. ships needed in order to cross the Atlantic Ocean. Franklin thought the Gulf Stream (墨西哥湾流) might explain this difference.
Franklin talked with captains of U.S. ships. He found that they knew each turn of the Gulf Stream. They used the current in every possible way. From his talks with the captains，Franklin made his first map of the Gulf Stream. Then he checked his map by using sealed bottles. The map that he finally made is still used, with only a few changes today.
答案是:（10分）
(1) Why are drifting bottles used? （2分） A To determine the position of a ship. B To find the direction of a current. C To predict the direction of a ship. D To carry message across the ocean. 正确答案B
(2) What led Franklin to talk with U.S. captains? （2分） A U.S. ships were longer than British ones. B British ships could sail the Atlantic faster than U.S. ones. C U.S. ships could sail the Atlantic faster than U.S. ones. D U.S captains knew more about maps. 正确答案C
(3) What did Franklin make after his talks with U.S. captains? （2分） A A map of the Gulf Stream. B A map of the Atlantic Ocean. C A map of ocean currents. D A map of his first voyage. 正确答案A
(4) What did Franklin do in order to make an exact map? （2分） A He compared his own map with other maps. B He talked with many U.S. captains. C He used drifting bottles to check his map. D Both B and C. 正确答案D
(5) The underlined word current in the first paragraph means __________. （2分） A a stream of water B a course of events C the flow of electricity D the situation of the present time 正确答案A
