As many as / for as long as (之多 / 之久)

Structure (verb) + figure/amount + 之多｜ (verb) + duration + 之久

之多 (zhī duō) and 之久 (zhī jiǔ) are emphatic nominal closers that stress that a quantity or a span is strikingly large. 之多 caps figures of number or amount: 参加者达上万人之多 = «as many as ten thousand people took part». 之久 covers the time axis: 持续了三年之久 = «it dragged on for as long as three years». The nuance is always astonishment at the magnitude; it belongs to literary and journalistic prose, and follows the figure or the period, never precedes it.

Examples

参cān加jiā者zhě达dá上shàng万wàn人rén之zhī多duō。
There were as many as ten thousand participants.
这zhè场chǎng战zhàn争zhēng持chí续xù了le三sān年nián之zhī久jiǔ。
That war dragged on for as long as three years.
报bào名míng者zhě达dá数shù千qiān人rén之zhī多duō。
Those who signed up numbered as many as several thousand.
这zhè场chǎng谈tán判pàn僵jiāng持chí了le半bàn年nián之zhī久jiǔ。
Those talks remained deadlocked for a full half-year.

Levels are indicative: they follow the standard Chinese Grammar Wiki (AllSet Learning) progression, not an official HSK 3.0 mapping. We never assign levels by eye.

This point and the other 370, with audio on every example, inside Wanyu.