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

False:

    中午我复习了两多小时。

    Zhōnɡwǔ wǒ fùxí le liǎnɡ duō xiǎoshí.

True:

    中午我复习了两个多小时。

    Zhōnɡwǔ wǒ fùxí le liǎnɡ ɡè duō xiǎoshí

多与数词、量词才能组成表示概数的词语。两多小时中缺少量词。应在个位数两和多的中间补上个。

Both a numeral and a measure word are required in forming a phrase with 多 to represent an approximate number. In 两多小时, the measure word 个 should be inserted between 两 and 多.