Book9 Unit2 Sailing the ocean 词汇&难句
I、Fill in the blanks with the words given in their proper form.
1. This seems to have been the first and most useful form of _______ (explore) which carried the minimum amount of risk.
2. _______ (accomplish)随机抽数字的软件有没有 navigators were able to use the North Star to plot their positions.
3. An early method of measuring speed involved throwing a _______ (knot) rope tied to a log over the side of the ship. 
4. The number of knots that _______ (be) counted during a fixed period of time gave the speed of the ship in nautical miles per hour.
5. However, it was awkward to use as one of the points of _______ (refer) was the moving ship itself.
6. As the ship rose and plunged in the waves, it was _______ (extreme) difficult to be accurate with any reading.
7. There was no secure method of measuring longitude until the 17th century when the British solved this ________ (theory) problem.
8. They increased their ability _______ (navigate) new seas when they used instruments.
linux删除的文件夹怎么恢复
9. Sea birds could be used to show the way to land when it was nowhere _______ (see).
II、Try to explain the following words underlined in your own way.
1. An early method of measuring speed involved throwing a knotted rope tied to a log over the side of the ship. 
2. A seaman would measure the sun's shadow and compare it with the height of the sun at midday. 
3. The sextant works by measuring the angle between two fixed objects outside the ship using two mirrors.
4. It was easier to handle because it was more portable.
5. Later, when seamen began to use the compass in the 12th century they could calculate longitude using complicated mathematical tables. 
6. Certain tides and currents could be used by skillful sailors to carry ships to their destination.
7. There is a special cloud formation which indicates there is land close by.
8. As the ship advanced through the water the knots were counted as they passed through a seaman's hands.
9. 荣耀50pronfc教程It proved to be the most accurate and reliable of these early navigational instruments.
III、Fill in the blanks with proper propositions
1. Sailors often saw seaweed in the sea and could tell ________ the colour and smell how long it had been them. 
2. Fog gathers java转abap需要多长时间________ sea as well as _______ streams or rivers
3. Then he could tell if he was sailing _______ his correct rather than a random course.
4. _______ a clear day especially during the summer the sailors could use the sun overhead _______ midday to navigate _______.
IV. Analyze the following sentence structures.
1.Nobody knew that the earth moved westwards 15 degrees every hour, but sailors did know an approximate method of calculating longitude using speed and time.
2. The voyages of travellers before the 17th century show that they were not at the
mercy of the sea even though they did not have modern navigational aids.
position of the day3. We may well wonder how seamen explored the oceans before latitude and longitude made it possible to plot a ship's position on a map. 
4. The number of knots that were counted during a fixed period of time gave the speed of the ship in nautical miles per hour.
5. The compass has a special magnetic pointer which always indicates the North Pole, so it is used to help find the direction that the ship needs to go.
6. The earliest, the astrolabe, was a special all-in-one tool for telling the position of the ship in relation to the sun and various stars which covered the whole sky. 
7. This was a more precise and simplified version of the astrolabe. It measured how high stars were above the horizon using a quarter circle js两个数组去重rather than the full circle of the astrolabe.
8. The sextant was the updated version of the astrolabe and quadrant which reduced the tendency to make mistakes.
9. This seems to have been the first and most useful form of exploration which carried the minimum amount of risk.
Feedback of your problems: _____________________________________
关键词语解析：
释疑导思
I.  mercy n 英文释义：___________________________________________________
归纳用法： at the mercy of 任凭…摆布 ；在…支配中
          show mercy on /to sb 对某人表示怜悯
          have mercy on  对……表示怜悯
          without mercy 残忍地，毫不留情的
beg for mercy乞求宽恕
联想：pity—pitiful;  sympathy—sympathetic  mercy—merciful
                                                                             
1.他们在海上迷失了方向，任凭海浪摆布
                                                                             
II. secure adj英文释义：__________________________________________________

版权声明：本站内容均来自互联网，仅供演示用，请勿用于商业和其他非法用途。如果侵犯了您的权益请与我们联系QQ:729038198，我们将在24小时内删除。