Translation:Please do not play any dangerous sports.
Do not play dangerous sports please should work but it doesn't. Why?
"Play" sounds very unnatural to me. Should just be "do" imho. -> "Please don't do dangerous sports"
'Do' wouldn't quite sound right to English speakers, however. Maybe 'engage in' might be a better option?
What is the rule in relation to verbs when using ...ないでください . Why does "Yaru" change to "Yara". I don't remember what I was taught in high school over 20 years ago.
ri > ra
ki > ka
shi > sa
When you look at all topics in your Japanese "Home" tab and choose this topic you will have two buttons: START and a light bulb. Click on the light bulb and it will show you how verbs should look like in the ないで form.
From what I know, やる is more for physical actions while する is more broad. Also, using this term infers that you are looking down upon someone, so using する is nicer and more versatile. Hopefully someone can confirm my understanding~