My son is in K1. He is 3歲 and 10 months now.
I think his 專注力 is OK.
I am a lazy mother. For the past X'max and Chinese New Year, he have 'a book' of homework, about 3x pages in each holiday.
I find that he can concentrate on his homework for about 50 mins. And then, he don't want to do his homework anymore.
i.e. 專注力 = 50 mins
Lucky, in 50 mins, he can finish half (about 16-17 pages) of his holiday homework. (just simply drawing......)