afterthought /ˈɑːftəˌθɔːt/

• 1. 

  N-COUNT If you do or say something as an afterthought, you do or say it after something else as an addition, perhaps without careful thought. 事后的想法; 马后炮 [usu sing, usu 'a' N]

  例：

  Almost as an afterthought he added that he missed her.

  几乎是后来想起来，他补了句他想她了。