The number of Chinese speakers in the world ______ with the

填 C.growing
The number of Chinese speakers in the world ______ with the development of China is much larger than ever before.
growing with the development of China是动名词短语 作状语或者叫插入语
这句话可以说The number of Chinese speakers in the world is much larger than ever before.

A 因为the number of 表示……的数量，谓语动词用单数，而且是一般现在时