"越 ... 越..." (yuè... yuè...) is used frequently in Chinese to express that some quality or state is increasing with time, or in tune with another factor. There are two forms of this pattern, the "simple" one (using 来), and the more complex one (which uses two different adjectives/verbs) in Chinese grammar.
Basic Structure with 越来越
This structure expresses that something is becoming more and more adjective over time, with the latter adjective changing with the verb. The most common structure is:
subject+越来越+Adjective
Examples
汽油 越 来 越 贵。
Complex Structure with 越 ... 越 ...
This structure can be expanded further by replacing 来 with another verb. This expresses that one change causes another change. To be exact, there are four structures to use. (The examples make it clear how this works.)
Structure 1
subject+越+Adjective 1+越+Adjective 2
Examples
挑战 越 大，我 越 兴奋。
Structure 2
subject+越+Adjective，越+verb
Examples
她 越 不高兴，就 越 不说话。
Structure 3
subject+越+verb，越+verb
Examples
我 越 学习 中文，越 觉得 中文 很 难。
Structure 4
subject+越+verb，越+Adjective
他 越 喝 碳酸饮料 越 胖。
Complex Structure with Complement
You can also use "越...越..." with a complement. In this case, "越" has to follow the "得". This construction usually uses "State complements" and "Result complements".
subject+verb 得+越...,(verb 得)越...
Examples
你 买 得 越 多 越 便宜。
