僕はアルクの月刊『子ども英語』雑誌でCool & Genki Englishの記事を書いています。 英語教室で使う表現を、ネイティブスピーカーの言い方でもっとかっこよくします。
At the moment I'm training teachers in India. One strange thing I've found is that if I ask them “Is this OK?”, everyone shakes their head! They actually mean “yes”, but to me and you we'd probably read it as “no”.
A similar thing can happen in Japan with the “maru” and “batsu” symbols. For example teachers often ask children a question and the children make a large circle above their head if it is correct. But to someone who doesn't know Japan they probably wouldn't know the gesture! And if you wrote “maru” on a piece of paper, in most English speaking countries people would think it means “wrong”. So when doing gestures, shaking or nodding your head clearly is probably best, and for writing things down, a tick or cross are the easiest to understand!
Shake your head or nod your head!