2 sentences

1. 既然大家意见不一，那我们就针对此话题辩一辩。

   jì​rán dà​jiā yì​jiàn bù​yī, nà wǒ​men jiù zhēn​duì cǐ huà​tí biàn yī biàn.

   Since everyone has different opinions, let's have a debate on this topic.

   Source: Dong Chinese Dictionary

2. 既然你已经认错了，就没必要再辩了。

   jì​rán nǐ yǐ​jīng rèn​cuò le, jiù méi bì​yào zài biàn le.

   Since you've already admitted your mistake, there's no need to argue further.

   Source: Dong Chinese Dictionary