Let's hear what he gonna say? let's hear what he's gonna say? 以上两句哪个对？怎译较好

Let's hear what he's gonna say.

=Let's hear what he is going to say

让我们来听听他要说些什么（隐含的意思是“听听他有什么说法/说辞）

口语中， Let's hear what he's gotta say 也常见

= Let's hear what he has to say

= Let's hear what he's got to say

意思和上句都差不多

这两句省略掉 be 动词 is 或助动词 has 事实上是有点草率，但口语比较不那么讲究。