— It's a pleasure to travel with you.
一 It's so kind of you to say so.
A:happy thing
B:difficult thing
C:terrible thing
如图, 一艘轮船由海平面上A地出发向南偏西40º的方向行驶40海里到达B地,再由B地向北偏西20º的方向行驶40海里到达C地,则A、C两地相距( )