若时钟由2点30分走到2点55分,问时针、分针各转过多大的角度?
The shop owner suddenly stopped talking with his mouth ________ like a big “O”. It was the President Xi Jinping.
Our parents are always c____ about our health and happiness, no matter where we are.
(Ⅰ)求角A的大小;
(Ⅱ)若B= π6 ,AC=4,求BC边上的中线AM的长.