Foreigners often make some strange mistakes in Chinese when they study the most difficult language--- ---Chinese. We try to analyze typical sentences to correct these errors.

         Xiǎo Wáng hé Xiǎo Lǐ lái le, nǐ wèn wèn tā.
False: 小王和小李来了，你问问他。
         Xiǎo Wáng hé Xiǎo Lǐ lái le, nǐ wèn wèn tāmen.
True: 小王和小李来了，你问问他们。

“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.