Worried that

This pattern is used to explain that an action was taken out of worry or concern that something might happen. The first clause expresses the potential negative event (the worry), and the second clause describes the action taken to prevent it or as a precaution.

Meaning & Usage

Meaning: "Worried that...", "afraid that...", or "in case..."

When to use: Use it to connect a potential future concern with a present or past action. It gives the reason why you did something, specifically highlighting the element of precaution.

Formation

It attaches to verb and adjective stems.

Vowel or ㄹ ending stem + -ㄹ까 봐:

오다 (to come) → 올까 봐 (worried it might come/rain)

살다 (to live) → 살까 봐 (worried I might live...)

춥다 (to be cold) → 추울까 봐 (worried it might be cold)

Consonant ending stem + -을까 봐:

먹다 (to eat) → 먹을까 봐 (worried I might eat...)

늦다 (to be late) → 늦을까 봐 (worried I might be late)

비 올까 봐 우산 가져왔어. / 살찔까 봐 안 먹어. / 늦을까 봐 택시 탔어.

While both patterns can indicate a reason, they have very different nuances.

-(으)ㄹ까 봐: Precaution for a Potential Event

This pattern is used when the reason is a worry or speculation about something that might happen. The action is taken as a precaution.

Example: 차가 막힐까 봐 지하철 탔어요.

Meaning: I took the subway in case there was traffic. (The traffic jam is a possibility, not a certainty.)

-아/어서: Reason for a Known Event

This pattern states a direct cause-and-effect relationship. The reason is a fact that has already occurred or is currently happening.

Example: 차가 막혀서 지하철 탔어요.

Meaning: I took the subway because there was traffic. (The traffic jam is a fact.)

Use -(으)ㄹ까 봐 for worries and precautions, and -아/어서 for direct, factual reasons.