ballpoint penn.原子笔圆珠笔走珠笔书写圆珠笔复数：ballpoint pens 例句1.A ballpoint pen is always used to do his exercises.他的作业总是用圆珠笔做。
2、May I try out thIs ballpoInt pen， please?我试一下这支圆珠笔可以吗3.I want a ballpoint pen.我要买一支圆珠笔。
4、Sometimes， I also buy some lotteries to try my fortune， yet the only prize I get from it is a ballpoint pen.有时候，我也会买一些彩票试试运气，但如今我得到的唯一奖品就是一支原子笔。5.Weird Fact: A mouse can fit through a hole the size of a ballpoint pen怪异的事实：能钻进圆珠笔洞大小的老鼠
