There is no simple or single factor that determines if a given site will be a savanna, but some factors seem to play important roles in their formation.

没有什么简单或单一的因素能决定一个给定的地点是否会成为热带草原，但部分因素似乎在热带草原的形成中扮演着重要的角色。

youdao

I think it is still unclear whether black holes play any role in the formation of the first galaxies.

我认为到底黑洞在最初的星系形成过程中扮演什么样的角色，这仍然是不清楚的。

youdao

Supernova remnants play an important role in stellar evolution by enriching space with heavy elements, and triggering new star formation by compressing interstellar gas.

超新星残骸以重元素填充宇宙空间，压缩星际气体促进新恒星的形成，因而在星体演化过程中扮演重要角色。

youdao

He was able to convince the Three Lions to break with their traditional 4-4-2 formation and play a far more attacking style.

WSJ: U.S. Soccer Could Use a Good Crisis

The first time a play, formation or strategy is used, it can create a big element of surprise.

WSJ: In Praise of the Copycats: The Knockoff Economy

They were transformed to the more secure and positive thinking side back on their Lancashire territory, but had initially found the defensive 4-5-1 formation of a miserly Birmingham difficult to play through.

BBC: Burnley 2-1 Birmingham