"I appear to know a lot."
Translation:Ik blijk veel te weten.
Regarding om, me too! The really useful information on http://www.dutchgrammar.com/en/?n=Verbs.Au11 appears to say it can be left out, not that it must - blijken is described as a 'disguised om verb'. I can understand it being optional, but here the answer makes it sound that you definitely must not use om with blijken?????
No, blijken is referred to as a DAT verb. Take a look again at the list (right column).
That means that it is incorrect to add the OM with blijken and all the other DAT verbs. The complete list of DAT verbs is: blijken, lijken, denken, hopen, beweren, schijnen, menen, beloven, wensen (beloven en wensen are also OM verbs).
To be specific, this page doesn't reference omitting "om," and neither does the page full of "dat" verbs. But to explain it how my spouse did, because blijk is a "dat" verb, om can't be used with it (in this context). There is a direct comparison in English with the same verb, and the understanding that "appears" is a "that" verb:
"I appear to know a lot." Which is a contracted version of:
"It appears that I know a lot."
"Ik blijk veel te weten." Which is a contracted version of:
"Het blijkt dat ik veel weet."
Because of the way "blijk" is used, you just wouldn't pair it with "om." It would be like saying "It appears about I know a lot." So there's no "om" in the sentence whether it's full or contracted.
I really wish the mods would have weighed in before now, considering there are questions here that are six years old with the same question, but I think this should piece together the answer.
According to that entry in dutchgrammar.com blijken is a DAT verb, meaning that it can start a dat clause. So, instead of: "ik blijk veel te weten", we could also say "ik blijk dat ik veel weet" (they both mean the same). So, no OM with DAT verbs. The complete list of DAT verbs is:
Beloven Beweren Blijken Denken Hopen Lijken Menen Schijnen Wensen