Either skiing or snowboarding is prohibited on a public road.
We are prohibited from skiing and snowboarding on a public road.
"公道でのスキーやスノーボードの滑走禁止"
禁止する prohibit
使い方 The regulation prohibits us from smoking in the office.
Either skiing or snowboarding is prohibited on a public road.
We are prohibited from skiing and snowboarding on a public road.
上の文ですが
No skiing or snowboarding on a public street.
一語であればorをandとするべきです。
No skiing and snowboarding on a public street.
日本 
