cannot vs. can not
The first spelling/grammatical mistake I always see, even in journals is the spelling for cannot. Cannot must be one word, just like today and tomorrow!
But, I see so many can nots!! You can still grammatically use can not in some contexts, like Can you not shake your leg when I’m in the room? You can just not shake, ok? -> You can not shake it.
As in, you can choose to not shake it rather than you being unable, incapable of shaking! But that’s not the context they use in those darn journals!