Re: Reduced relative clauses
With the second set, the second sentence could lead you to believe they are currently taking the course. You would have to add something like "taking this course next term" or "next month" or something to avoid that ambiguity. It's perfectly grammatical, but it may not be a precise as you want it to be.
Originally Posted by aysaa
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.