by JonathanSchneider Sun Nov 30, 2008 1:09 am
It's a good question. First of all, there is a slight error in your grammar. You could fix it with the following:
John, who knows a number of exercises, carefully coordinates them with the instructor.
Your question is: can the "them" refer to "exercises" if "exercises" is not part of the core of the sentence? Yes. This might not be the ideal version, but it is acceptable. Cases like this one may oftentimes be complicated by other plural nouns, making the reference of "them" unclear. Watch out for that.