The engine is the ZMachine, and depending on the target and the grammar (IF6+English, or better, i7) the 'guess the verb' issue straightly died in the 90's.

Your comment coudn't be more outdated since the Curses! release for the ZMachine in 1993.

The v5 machine release was much better than the v3 one, and the v5-V8 ones allowed semi-complex phrases with indirect object pronouns after a previous entered phrase and much more.

Go play Anchorhead and compare it to a z3 machine game from Infocom, or any game made it with Puny Inform.