[Grammar] is currently the fifth of the world's megacities.

[ambitious-girl]

Hello all,
I want to know why the author used the plural form of the noun "megacity" here?
Shanghai, with a population of around 23.5 million, is currently the fifth of the world's megacities.

Source: American English File 4

 

[ambitious-girl]

It contrasts with Persian language. Thanks Piscean. So helpful.

 

[teechar]

It's not the same in [STRIKE]contrasts with[/STRIKE] Persian. [STRIKE]language.[/STRIKE]

Really?
Would you use the singular in Persian in the structure below?

is currently the fifth of (all) the world's megacities.

Perhaps you're thinking of:
... is currently the fifth-largest megacity in the world.

 

[ambitious-girl]

is currently the fifth of (all) the world's megacities.

With "of" added, now it makes much better sense.

Perhaps you're thinking of:

Yes.

Would you use the singular in Persian in the structure below?

No. In the structure above, we use plural. Also, if we have "all" or the preposition "of", we use plural form too. However, we almost always use singular form in sentences like:

There are four tree here.
I have two sister.
He has two wife.
This house has four window.

 

[teechar]

That's interesting. Thanks for that info.