There are two main lines of research.

有两条研究主线。

youdao

Seeing from full text, the article establishes in two main lines.

从全文来看，文章建立在两条主线之上。

youdao

As the defending team lines up a four-man wall, the captain of the attacking team discusses the options with his two main free-kick takers.

当防守球队排成四人一队的人墙，攻击球队的队长与他的两个主要任意球罚球球员讨论选择。

youdao

About 250 investigators are pursuing two main lines of inquiry - an Islamist motive or the far right.

BBC: Toulouse school killer 'had camera around his neck'