I don't think it's right to speak ill words when someone is not around.
我认为在背后说别人坏话是不对的。
I don't think it's right to make such a hasty decision.
我认为如此仓促地做决定是不对的。
I don't think it's right to smoke in public.
我认为在公共场合抽烟是不对的。