"They can not read."
Translation:Mereka tidak bisa membaca.
From oxford dictionaries :
Both "cannot" and "can not" are acceptable spellings, but the first is much more usual.
You would use can not when the ‘not’ forms part of another construction such as ‘not only’. For example:
"These green industries can not only create more jobs, but also promote sustainable development of the land."
--- end Thought it is better to use "cannot", in bubble puzzles exercises, "can not" is more suitable, i think.