单项选择题
A list man would expect to see any of the following light signals except （）.
A.two red lights B.one green light C.one white light D.one amber light
单项选择题 A line of position from a celestial observation is a segment of a （）.
单项选择题 A line of position derived from a loran reading is a section of a(n) （）.
单项选择题 A light used to signal passing intentions must be an （）.
