sports day的复数形式怎么拼写

sports day的音标：...

It will doubtless rain on sports day.开运动会那天多半会下雨.The rain fortunately held off till after the school sports day.幸亏雨直到学校运动会开过了才下.Twenty First of January is the anniversary sports day of our school.一月二十一日是我们的校庆运动会....

n.（学校的）运动日...