Can't help (feeling): không khỏi

Không khỏi before a feeling means "can't help feeling": không khỏi bất ngờ (can't help being surprised), không khỏi lo lắng (can't help worrying), không khỏi xúc động (can't help being moved). Khỏi here means to escape, so the phrase says the feeling couldn't be avoided.

It goes after the person and before a feeling word, usually of two syllables: Nhiều phụ huynh không khỏi lo lắng. The cause often comes with trước (in the face of) or khi (when): Du khách không khỏi bất ngờ trước vẻ đẹp của hang động.

You'll meet it in news reports and feature stories, describing how people reacted, and in personal essays. It's a stock phrase with a fairly small set of feelings: surprise, worry, emotion, regret (tiếc nuối), unease (băn khoăn).

Watch out for khỏi on its own in Saigon speech. There, khỏi + verb means "no need to": Khỏi lo! No need to worry! So khỏi lo means don't worry, while không khỏi lo lắng means can't help worrying, almost the opposite.

In conversation, people just name the feeling: Nghe tin đó em lo ghê, I was really worried when I heard.