10. 請參考所附六分儀構造圖，圖中標示為「C」之部位，其英文名稱為何？ (A) Horizon glass (B) Horizon shade glass (C) Index mirror (D) Index shade glasses

12. A vessel is seen showing three shapes in a vertical line; the top and bottom ones are black balls and the middle one is a black diamond. What does this daytime signal indicate? (A) It is a vessel engaged in dredging. (B) It is a vessel restricted in her ability to manoeuvre. (C) It is a vessel at anchor. (D) It is a vessel engaged in a mine clearance operation.