「China has many people」 is fine grammatically and practically.
Trying to find fault in this sentence is like splitting hair.
One argument I can see is the age-old debate whether an inanimate object (such as 「country」), could 「possess」 something with the word 「has」.
However, it』s been long accepted that 「country」 in possessive form, such as 「country』s leader」, or「country』s population」 (2.2 million in Google search), is fine.
Having said that, I would say "China has a large population". Its purely a matter of style and I am not claiming that sentence is better than "China has many people".
這種用法在口語中很普遍,例如下面幾句都是和老外聊天的時候對方用的:
Is Xian the city which has biangbiang面?
Yes, Britain has a lot of accents for sure!
I think airports and tourist attractions around the world tend to have thieves and scammers.
但是題目中那句,感覺有點怪怪的,如果是說 中國有很多人XXX,China has many people who XXX, 就更自然一些。如果就是說「中國人口眾多」, 那麼說 China has a large population 更好點。
他們一般都說「lots of」 或者「a lot of」,比如說「He has a lot of partners」而不是「He has many partners」,儘管後者語法完全正確。我問過一個英國人,為什麼口語里不用many,他說因為很多人懶得區分可數還是不可數,many和much全都用「lots of」代替很方便。
而為什麼用「There are a lot of people in China」,而不是「China has a lot of people」,原因在於前者更像是一句完整的句子,後者聽起來像是話講了一半。英國人會以為你要說「China has a lot of people doing sth.」 然後下半句那個「doing sth」等了半天一直沒出來,發現你原來早就說完了,真是讓人摸不著頭腦,哈哈。
比如他們會說,"Barclays has a lot of branches opening on Sunday morning."(巴克萊銀行有不少分店周日早上開門)這才是「xx has a lot of xx……」的常規用法。
當然最好還是說"China has the largest population"更準確一些,畢竟要強調的是「人口」這個詞。