@Kate & craigrut,
One little problem with the sentence 如果你触摸我的东西我就杀死你 is 触摸 is very formal, so we can use it in a sign like 请勿触摸, but not in a normal sentence. If we want to make the sentence sound more natural, we should say 如果你摸我的东西我就杀了你.
--Echo
echo@popupchinese.com