we don't have an exact equivalent to 想通. so it depends on the context what we might say. it seems that "想通" most closely corresponds to "to come around to <an idea>", but we don't say this very often. so, we could translate it as, this morning, I finally came around to something. 但是基本上，要看［一件事］是甚麼樣的事， 才能更好地翻譯

Early this morning I finally realised something. Early this morning I had an epiphany. Early this morning a light went on. Early this morning the penny dropped. I can't think of any more.

I think ,we can transelate it in tho english like this" Today mornig ,I eventually got through an incident."

“今天早上我终于想通了一件事。”用地道英语怎么说。 This morning I finally gained clarity regarding an issue. This morning I finally became clear about the issue.

I finally got something figured out this morning. I finally convinced myself of something this morning. I finally came up with a conclusion of something this morning. I finally got the right idea about something this morning. I finally put together my thoughts about something this morning. 本人想了一些句子，不知够不够地道，等待母语人士检阅。:) （这些句子可能跟辞典里的都不一样，我觉得辞典或者软件的翻译经常不能令我满意。）