在直角坐标系中,椭圆的参数方程为(为参数,).在极坐标系(与直角坐标系取相同的长度单位,且以原点为极点,以轴正半轴为极轴)中,直线的极坐标方程为,若直线与轴、轴的交点分别是椭圆的右焦点、短轴端点,则 .
Libraries or reading corners (build) in hope primary schools along the way of Long March in a few years.
My daughter is much (tall) now.The jeans she wore last year are already too short.
This machine can (translate) simple messages into 24 different languages.
Wild animals which are now in danger need our (protect).
More than six (百) teams took part in 2017 Nanjing primary and secondary school robot
competition in May.