For example:

"Some variations on the activity" vs "Some variations of the activity".


"practise vocabulary on pets" vs "practise vocabulary of pets".

What is the difference in terms of meaning and when do you use each?

closed as off-topic by Jim, user140086, Dan Bron, MetaEd, choster Jul 25 '16 at 18:53

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  • I don't think I can give you a hard and fast rule that applies to all usages. However, I do recognize these ones: variations of means "instances of a changed thing", variations on usually means "a thing [usually a musical theme] with small modifications", vocabulary of means "words used by or referring to [a group or topic]", vocabulary on is uncommon. Your best bet to solve this sort of problem is look up variation or vocabulary in a dictionary and check which prepositions are used in the examples. – Benjamin Kuykendall Jul 25 '16 at 6:05
  • The examples you're giving aren't grammatically similar enough to compare, as the first is a fragment with no verb. The difference in the second example is the difference between, "Practice [human] vocabulary on pets, " -- presumably because they won't be judgmental about your grammatical errors, and, "Practice barking." – webbcode Jul 25 '16 at 18:48