Thanks. That's what I suspected. I didn't know about all the mappings. I think you've mentioned one or two of them before. LOOK AT is mentioned in the doco.
I was also wondering how to implement LOOK UNDER (as in "look under the rug") and LOOK THROUGH (as in "look through the window"). LOOK is a synonym for EXAMINE, but EXAMINE UNDER and EXAMINE THROUGH are a bit dubious. I suppose I could use a test like:
: if (original_verb() == "look" && preposition_is "under")
Anyway, it's overkill for now, so I'm just going to ignore those possibilities.