实用口语：我突然想到(我钥匙落办公室了)

It just came to me (that)…我突然想到

e.g. It just came to me that I left my keys in the office. I'll have to go back and get them. 我突然想起我把钥匙忘在办公室了。我得回去拿。

e.g. It just came to me that I should apologize to Jane for what I said earlier. 我突然想到我应该向简道歉，因为我之前说了些不该说的话。

e.g. how'd you think to do all this? I don't know. It just came to me.  你怎么会有做这些事情的想法的? 我也不知道, 我就突然想到的.