我不清楚。

You can use this phrase as a standalone answer or as a prefix. If someone asks for directions, you can simply say 我不清楚. If you want to be more specific, you can say 我不清楚他在哪里 (I'm not clear on where he is). It works beautifully in both spoken and written Chinese. It’s a very safe 'default' phrase for your vocabulary toolkit.

Use this when you want to sound professional or polite. It’s great at work when a boss asks for a status update you don't have yet. It’s also perfect for tourists when a local asks them for help. It makes you sound like a person who *wants* to be helpful but just lacks the data. Use it when you are 80% sure but don't want to be held responsible if you're wrong.

Avoid using this if you definitely *should* know the answer. If your mom asks if you brushed your teeth, saying 我不清楚 sounds like you’re a robot or a politician avoiding a scandal. Don't use it in very high-stakes emergencies where a quick 'Yes' or 'No' is needed. Also, with very close friends, it might sound a bit too 'office-speak'—try a more casual 不知道 instead.

In Chinese culture, 'saving face' is a big deal. Saying a flat 不知道 (I don't know) can sometimes feel dismissive or even a bit rude. It shuts down the conversation. 我不清楚 is softer. It implies that the information exists, but it hasn't reached you yet. It keeps the social harmony intact. It’s the 'diplomat’s choice' for admitting ignorance without looking uninformed.

You can add 不太 (bú tài) to make it even softer: 我不太清楚. This means 'I'm not too clear,' which is the ultimate polite hedge. In the south of China or Taiwan, people might add a 喔 (o) at the end to sound friendlier. If you want to sound very formal, you could say 我并不清楚, where the 并 adds emphasis like 'I really am not clear on that.'