Why can we say:
It is worth more than. . . .
It is expensive more than. . . .
It’s the position of more which I find so confusing.
Also, is worth an adjective in both these cases?
Expensive is behaving as a typical adjective, which are only modified by preceding degree words, e.g.
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.
The phrase is worth behaves likes a stative verb. The only other comparable phrase I can think of is [be] up/down as in:
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
What is interesting is that although an expression like
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:
I'd say worth is an unusual word, and has only become more unusual in recent history.
Worth is a difficult word.
In this particular case, worth is behaving transitively, since it has a complement with a comparative construction: more than . . . .
Expensive, on the other hand, is an ordinary adjective and has to be either a predicate adjective
or an attributive adjective
And the comparative construction places adjectives after more, not before more.