航海英語海圖及海圖作業(yè)單項(xiàng)選擇題每日一練(2019.01.10)

來源：考試資料網(wǎng)

1 When a buoy is in position only during a certain period of the year，where may the dates when the buoy is in position be found?（）

2 The agonic line on an isomagnetic chart indicates the （）.

3 A Mercator chart is a （）.

4 （）is not a position-fixing system.

5 The changes in the channel’s sands and buoys on this coast are （） this chart can not be considered as a safe guide of the channel．