Multiple Number Comparatives

 Petrol is twice as expensive as it was a few years ago.

Their house is about three times as big as ours is.

Mary types twice as fast as I do.

When something is compared with another thing according to their numbers, the sentence follows a different structure. Multiple number comparatives include half, twice, three times, four times, etc.

Structure:

Subject + verb + number + as + much/many + (noun) + as + noun/pronoun + verb

Examples:

 - John has half as many wickets as Watson has.
 - Robert works twice as much as Alex does.
 - I have three times as many runs as he has.