I was speaking with a friend of mine and said I learnt Japanese using some dictionaries and websites. But I forgot to mention that I also use grammar books, so I said:
忘れてた！日本語の文法書たくさんよんでいますね。 I forgot! I read many Japanese grammar books.
She then corrected me saying it should be 見忘れました instead, hinting that with 忘れてた (or 忘れました） you can't drop what was forgotten (i.e. it needs to be explicitly said e.g.
〜を忘れてた I forgot .
Does the 見 at the start of the verb make the transitive verb (requiring an object) into an intransitive verb (not requiring an object)?
The dictionary definitions I have don't show much difference:
見忘れる【みわすれる】 v1,vt + (1) to forget/to fail to recognize/to fail to recognise/EntL1641770X
忘れる【わすれる】 v1,vt Pop + (1) to forget/to leave carelessly/to be forgetful of/to forget about/to forget (an article)
Possibly related: https://japanese.stackexchange.com/a/15118/10888
EDIT: Full conversation below (please ignore spelling mistake of 見忘れました as みわせれりました