Expensive is behaving as a typical adjective, which are only modified by preceding degree words, e.g.
It was more expensive than...
It was more sudden than...
It was more amazing than...
If we pretend for a moment that is worth was a verb, we could compare it with some other verbs of measuring activites, e.g.
It weighs more than...
The room seats more people than...
It measures more than...
It costs more than...
The phrase is worth behaves likes a stative verb. The only other comparable phrase I can think of is [be] up/down as in:
The Lions are down three points.
The Lions are up more than the Bears were up at this point last week.
If worth is an adjective, then it is one which is almost always restricted to being a predicative adjective. This is how Oxford English Dictionary (OED) describes it, noting that it is used
Almost always (now only) in predicative use, or following the n. as part of a qualifying phrase.
What is interesting is that although an expression like
*Gold is more worth than silver.
with a preceding degree word, would be usually considered ungrammatical, there are several attestations listed in OED of exactly such a usage (where a degree word precedes worth) from the Early Modern English period:
1568 Newe Comedie Jacob & Esau ii. iv. C iv b, Ah sir, when one is hungry, good meat is much worth.
1581 G. Pettie tr. S. Guazzo Ciuile Conuersat. (1586) iii. 138 It may rightly be saide..that the feathers are more worth then the byrde.
1615 W. Lawson Country Housewifes Garden (1626) 6 Fruit blown vnripe, are small worth.
I'd say worth is an unusual word, and has only become more unusual in recent history.
Who told you the second one was "not correct?" I don't think "not correct" is quite the right way to say it.
I think this has to do with the word knowledge more than the word English. When talking about any kind of knowledge, I can see where a textbook teaching formal English would recommend saying:
knowledge of X
or
knowledge about X
over
X knowledge.
After all, in these expressions:
- coin knowledge
- car knowledge
- garden knowledge
words that are mostly known as nouns are being put to work as adjectives. So a textbook might say that it would be better to use, knowledge about coins, cars and gardens.
However, in reality, such nouns are pressed into use as adjectives all the time.
Fact is, the expression English knowledge can be found in published works academic studies, as evidenced by anecdotes found here, here, and here.
However, as Edwin points out in his comment, the phrase "English knowledge" is ambiguous; it can mean knowledge possessed by the English, not knowledge about English, as is the case here.
I would say that knowledge about English might be more formal, or more syntactically precise, but I'd be hesitant to call the other "incorrect."
Best Answer
Sure, you can say the world is handsome. It's just that the word "beautiful" has worn a path in our language regarding the world.
Handsome can also mean imposing, or of great size, as in "a handsome prize" or "a handsome sum of money"; and you can use any human-descriptive adjective you like, really, if you are speaking figuratively and employing the pathetic fallacy.