The second part of a comparison (underlined) is often a clause:
The price washigherthan we had expected.
That restaurant isnot as goodas it used to be.
It wasthe bestnature documentaryI’ve ever seen.
Than-clauses
We can usethanto introduce a clause after a comparative adjective, adverb or noun phrase. The clause (underlined) is usually a reduced clause (a clause with ellipsis) or one with a substitute verbdo:
The house wasbiggerthan we had imagined.(… bigger than we had imagined it was)
The journey tooklongerthan expected.(… longer than people expected it to take)
He finished the second partmore quicklythan he did the first part.(… more quickly than he finished the first part.)
He always spentmore moneythan George did.(… more money than George spent.)
We usethan, notthatoras, to introduce a clause after a comparative adjective or adverb:
We finished the job quickerthanwe had expected.
Not: …quicker that we had expected. or …quicker as we had expected.
See also:
Ellipsis
Substitution
That-clauses
We can use athat-clause after a superlative:
Until 2005, the film had made the most moneythat any British film had ever made.
In informal situations, we can omitthat:
It was the biggest fire(that) anyone had ever seen.
It was the least expensive restaurant(that) we ate at, but the food was excellent.
See also:
Comparative and superlative adjectives
Adverbs: comparative and superlative forms