“I'll tell more. I could tell you why they did it.”
我还能说更多。我可以告诉你们他们为什么这么做。
一句承诺把悬着的故事又往前推一步,勾着人非听下去不可。
I could tell you why ...
想吊人胃口、表示还留一手时用;正式汇报里别这样卖关子。
There's more where that came from. / I can tell you the reason behind it.
口语
tell more 连读,why they did it 一气呵成收尾。
I could tell you why the deal fell through. 我可以告诉你这单生意为什么黄了。