— Why do you look sad?
— There are so many problems _____.
A:remaining to settle
B:remained settling
C:remaining to be settled
D:remained to be settled
两个板块发生张裂的地带,常形成( )
①裂谷 ②山脉 ③火山 ④海洋
如图,一艘轮船在A处测得灯塔P位于其北偏东60°方向上,轮船沿正东方向航行30海里到达B处后,此时测得灯塔P位于其北偏东30°方向上,此时轮船与灯塔P的距离是( )