Did you ever read the manuals? Every single one of them had a section that gave you an idea of basic commands common to all adventures, as well as ones specific to whatever the particular game was doing - Suspended's set of six robots, Enchanter's spellcasting, Deadline's character interation and interrogation, Nord & Bert's goofy wordplay, etc.

Didn't some of them respond to the "help" command, at least to list basic verbs?

I agree they were pretty hard to win, but at the same time, when you figured out the solution to a puzzle it was pretty satisfying.

Modern IF games play with this trope of "hard to guess the exact words/solution". Some will incorporate the wrong input into the theme, as in that spaceship game were typing invalid input will make the game respond with "bzzzt... didn't get bzzttt that... you're bbbzrzzt up, can you bzz repeat?".

In others, like Spider & Web, where you're being interrogated, the "wrong" action will make the interrogator respond "that's not what happened, don't lie to me".

In "Photopia" there's a maze puzzle you cannot actually win because the game is intentionally withholding information from you. When you give up, the game frees you by telling you the one detail you missed.

I do agree I didn't finish most of the "oldschool" text adventures, though.

The zork maze had me befuddled as a child. Then I saw a map a realized the location weren’t on a grid so going North then South wouldn’t end you up in the same place..

I got pretty far in a few of these but only finished one. I think the pc versions had better in game hints than the Apple //e ones did.