Increasingly,副詞，一般用法都是be/become Increasingly adj.表示日益，越來越多地，不斷增加的"adj"，所以如果要替代的話最好是把主語變成回國發展的留學生人數，the number of Chinese oversea students who comes back to China to hunt better working chances become increasingly large.

或者可以直接用increasing，the number of Chinese oversea students who comes back to China to hunt better working chances is increasing。

the increasing number of 的意思是····數目的增加；例：

1.the increasing number of tourists to China .

隨著來中國旅遊人數的增加。

2.The base of perianth tube was commonly bent , and had relativity the increasing number of tepals .

花被筒基部彎曲變異也較常見，而且與花被裂片數目增多的變異存在相關性。

an increasing number of 的意思是不斷增長的…數目；越來越多的。例：

1.An increasing number of bacterial skin infections are resistant to antibiotic medicines .

皮膚被越來越多的細菌感染會導致對抗生素的耐藥。

2.They note that an increasing number of similar tests are available to process cells , genetic material and proteins .

他們提到越來越多的，與此類似的實驗可以被用在細胞處理，基因原材料和蛋白質。

incresing number of 前面一定要加冠詞。因為number是可數名詞。後面可以加單數名詞，也可以加複數名詞。

另外：a growing number of=a incresing number of =more and more.