Hello.

I bet there was a misunderstanding on num 17's marking.

You mentioned,

you could have also mentioned that we should try to keep an eye on our students while writing on the board.

But, I bet my response,
"teachers can check whether students are paying attention to the class or whether they cannot understand the explanation well or not"
is talking about the same thing.

Do you mind talking about this more deeply?

Thank you.