When communicating in Chinese you may often make mistakes using Chinese grammar like:

False:

    小王和小李来了，你问问他。

    Xiǎo Wáng hé Xiǎo Lǐ lái le, nǐ wèn wèn tā

True:

    小王和小李来了，你问问他们。

    Xiǎo Wáng hé Xiǎo Lǐ lái le, nǐ wèn wèn tāmen.

“他”指代不清，是问“小王”还是“小李”，看不出来。应改为“他”为“他们”。

他 is ambiguous since it directs at 小王 or 小李 with equal possibility. 他们 should be used.