Expressing "some" with question words

This article is a stub. Editors can help the Chinese Grammar Wiki by expanding it.

当不知道、说不出来或不便明说某事、某人、处所、时间、方式等信息时，可以用疑问代词“什么、谁”或疑问副词“在哪儿、什么时候、怎么”来虚指。

以"在哪儿"为例，句型一般是：

Obj. + Subj. + 在哪儿 + Verb + 过

More examples with different question words:

Examples

这个人我 在哪儿 见过。Zhège rén wǒ zài nǎr jiàn guo.I met this person somewhere.
这首歌我 在哪儿 听过。Zhè shǒu gē wǒ zài nǎr tīng guo.I've heard this song somewhere.
你让谁来帮我一下。Nǐ ràng shéi lái bāng wǒ yīxià.Ask somebody to help me with this.
这件事我听谁说过。Zhè jiàn shì wǒ tīng shéi shuō guo.I've heard someone say this before.
我们应该做点儿什么。Wǒmen yīnggāi zuò diǎnr shénme.We should do something.
老大，你不说点儿什么？Lǎodà, nǐ bù shuō diǎnr shénme?Boss, are you going to say something?
我的自行车不知道怎么坏了。Wǒ de zìxíngchē bù zhīdào zěnme huài le.My bike was somehow broken.
他不知道怎么生气了。Tā bù zhīdào zěnme shēngqì le.He got angry for no reason.
什么时候 我们见面谈吧。Shénme shíhou wǒmen jiànmiàn tán ba.We should talk about this sometime in the future.
什么时候 你来我新家玩吧。Shénme shíhou nǐ lái wǒ xīn jiā wán bā.You should come to my new house to hangout sometime in the future.