This sentence isn't correct.I can't figure what this sentence wanna say. Maybe it's'北京还将有20多个胡同'. 将=will/going to

This sentence should be:北京还将有20多个胡同 since you need a verb"have/has" to make the sentence grammatically correct.But you can just use "there be" in English which has the same meaning as "XX有“ It's "There will/going to be 20 lanes(or simply use Pinyin" Hutong") in Beijing.

句子不完整，incomplete sentence. 北京还(有)将(近)20多个胡同？ Beijing has around 20 alleys? But Beijing 's number of alley can;t be only 20..

English is not very good, this probably means: The upcoming 将……即将 Same meaning “北京还将20多个胡同” 这句话并不通顺，应该这样子： “北京还将保留20多个胡同” 或者 “北京还将取消20多个胡同”