"心中暗想"的英文表达可以是 "think to oneself" 或 "think silently to oneself"。这个短语表示的是一个人在没有告诉任何人的情况下，在心里面想着某件事情。

例如：

"I can't bepeve he said that. I was thinking to myself, how could he be so rude?" (我简直不敢相信他说了这么糟糕的话。我在心里暗想，他怎么会这么无礼呢？)

"She thought silently to herself as she walked home. She knew she had made a mistake, but she wasn't sure how to fix it." (她一边走回家一边心中暗想。她知道自己犯了一个错误，但不知道如何弥补。)

这个短语通常用在口语中，表示一个人在不与他人交流的情况下，在自己的心里思考某件事情。