不禁 (bù jīn): Cannot refrain from (Adverb) — Meaning & Stroke Order

Hearing this good news, he couldn't help but laugh.

Looking at this painting, don't you find it makes one involuntarily contemplate?

He did not become complacent with success; on the contrary, he spontaneously felt a great sense of responsibility.

Smelling the aroma wafting from the kitchen, I couldn't help but wonder what's for dinner tonight.