A pang is a sudden strong feeling or emotion, for example of sadness or pain.
①For a moment she felt a pang of guilt about the way she was treating him.
②She experienced a sharp pang of disappointment.
Romain Gary的小说 Promise at dawn 也出现了这个表达：
~ of pain, fear, etc. (literary) a sudden strong feeling of pain, etc. that travels through your body.
Shafts of fear ran through her as she heard footsteps behind her.
[scode type="blue"]beef up
If you beef up something, you increase, strengthen, or improve it.
①Both sides are still beefing up their military strength.
②Earlier Kerry addressed state department trainees about beefing up security for diplomats.
《经济学人》一篇关于地缘政治与芯片之争的文章 Betting all the chips 也出现了这个表达：
beef作为动词还可以表示“不断抱怨；大发牢骚”【If someone beefs about something, they keep complaining about it.】