航海英語海圖及海圖作業(yè)單項選擇題每日一練(2019.01.19)

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 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．

3 The maximum difference between mean time and apparent time is （）.

4 What defines a great circle? （）

5 The description Racon beside an illustration on a chart would mean a （）.