如图,两座建筑物的水平距离BC=30m,从A点测得D点的俯角α为30°,测得C点的俯角β为60°,求这两座建筑物的高度.
I have a good friend.She is a beautiful girl.She is lovely.She has two big eyes and she's thin.Her favourite colour is red.She likes wearing(穿着)a red dress.She can sing and dance.We often(经常)play together.
如图为人体新陈代谢的过程示意图.