题干
When National Day comes, we have a _____ holiday.
A：seven-day
B：seven-days
C：seven days
D：seven day
答案(点此获取答案解析）
A
When National Day comes, we have a _____ holiday.
A：seven-day
B：seven-days
C：seven days
D：seven day
, 灯塔A在观察站C的北偏东
, 
，则灯塔A与灯塔B的距离为（ ）
