Student or Learner
Dear Forum Users,
In the parentheses I want to express that Xs usually express Y. Can I say ...
In cases when Xs express Y (as they generally do/as they generally do so) ...
So, is 'so' needed or not?
No it's not. It's only needed in cases like 'You know you should take your shoes off. Do so.' Here it's behaving a bit like a pronoun, in that you could say either 'Do it' or 'Do that'. But whereas it and that can be used to refer back to things as well as actions, so can only refer to actions (so look for a verb if you're in doubt about whether to use it).