Kate won the _____ race in the summer sports meeting.A 100-metre B100-metres C 100 metre 100 meter's 能帮我解释下为什么选A嘛? 谢谢

Kate won the _____ race in the summer sports meeting.A 100-metre B100-metres C 100 metre 100 meter's 能帮我解释下为什么选A嘛? 谢谢
Kate won the _____ race in the summer sports meeting.
A 100-metre B100-metres C 100 metre 100 meter's 能帮我解释下为什么选A嘛? 谢谢

Kate won the _____ race in the summer sports meeting.A 100-metre B100-metres C 100 metre 100 meter's 能帮我解释下为什么选A嘛? 谢谢
A：这是一种固定的用法

100-metre
或者100 metres '
两种都行

没有为什么，百米赛跑有两种写法：100-meter 或者100-meter