How can you tell which direction? By day, look for the Sun. _____________________________________________. At night, use the Big Dipper to help you find the North Star. It would be better to bring a compass because its needle always points north.
How do you know how far you have gone? ____________________________. Each step is about two feet. You’d better wear a pedometer which is a tool that counts steps. If you know where you started, which direction you are heading, and how far you have gone, you can use a good map to figure out exactly where you are.
Today there is a new way for travelers to figure out where they are. It is the GPS. It has 24 satellites that orbit the earth and ________________________. Someday you may carry a small receiver as you hike and use GPS to find out if you are there yet!
Useful Words and Expressions:
dipper 北斗七星
compass 罗盘
pedometer 步数计
GPS= Global Position System 全球定位系统
orbit 轨道，绕……轨道而行
receiver 接收器
it 's in the east in the morning and west in the afternoon. at night, use the big dipper help you to find the north star.it will be better to bring a compass because it's needle always point the north.
you could count every step.
constantly broadcast the positions
发表于 2014-11-20 10:21
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发表于 2014-12-10 09:45
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