"他的爸爸经常读历史书。"

Translation: His dad often reads history books.

[dTanMan]

"His father 'frequently' reads history books" has been suggested to be an acceptable answer.

[Elijah.Fung]

his dad often reads historical books. 不对吗

[VictorKean1]

"Regularly" was not accepted as an answer.

[EmiLithium]

Jing Chang can mean always, regularly, frequently. These synonyms should be accepted.