如图,在一密闭的圆柱形玻璃杯中装一半的水,水平放置时,水面的形状是( )
A:圆
B:长方形
C:椭圆
D:平行四边形
51-50=____ 64-60=____ 57-4=____
37-5=____ 94-80=____ 58-7=____
从右栏中找出左栏各句的应答语。
①What does he look like?____ A. It's yellow.
②Is his bike new?____ B. Yes, they are.
③Whose book is this?____ C. He has gray hair.
④Are these your apples?____ D. Sorry, I don't know.
⑤What color is your coat?____ E. It's mine.
有一艘渔船上午九点在A处沿正东方向航行,在A处测得灯塔C在北偏东60°方向上,行驶2小时到达B处,测得灯塔C在北偏东15°方向,求∠C的度数.