底线球的英文：
baseline ball

参考例句：

Baseline Ball
底线球

baseline是什么意思：
n. [计]基线

Baseline values for any of the parameters reported did not differ statistically between the egg treatment groups.
任何参数的基线值,在不同实验组中从统计学上说差异不显著。

Inferior characters: Letters or numbers which ar4e smaller than text size and are positioned on or below the baseline.
下标字符:较内文字为细的字母或数字，放置于基线或更低位置。

The earth moving around the sun gives us a baseline for measurements of objects outside the solar system
地球绕太阳公转，为测量太阳系外的恒星距离提供了一条基线。

ball是什么意思：
n. 球；舞会
v. 成团块；捏成球形

You have no balls!
你们一点胆量都没！

The kitten tangled the ball of yarn.
猫把线团儿弄乱了。

A ball hissed by.
子弹嘶地一声飞过。

The dog had itself a ball.
狗玩得很愉快。

Do you have the balls to challenge authority?
你有挑战权威的胆量么？