I have been looking at some of my courses and different groupings (Levels - MemRise term) would test on different aspects of a course.
At present all I can do is set learning to test once and plough through until I get to the bit I am interested in.
Also some very long courses might have very simple words (days, numbers etc) but get more complex later on.
So it would be nice to be able to select the range one would like to be tested on.
Incidentally at present we can only see 20 items when learning but the "Overview" shows all entries so perhaps we need to see the full course list of words or phrases and still select how many we want to be tested on in that range.
The only other solution I can think of, is to arbitrarily break the course into 20 word segments so it's quick to select a range further down. MemRise offered that function when creating a course that did not have levels by topic.
Something for a rainy day @neoncube?!