parabola mass spectra

例句：

1. 1. The parabola is the shape of a curvethat looks like an inverted letter"U".
   抛物线是看起来像倒写的字母“U”的曲线形状。
2. 2. The parabola passes through thecenter of the circle.
   抛物线穿过圆的中心。
3. 3. The parabola is usedto describe the path of a projectilewhen it is thrown horizontally.
   抛物线用于描述当弹丸水平抛出时的运动轨迹。