What are the difficulties of translation to Arabic language?

Tenses are the most difficulties in translation to arabic, because in English we have many tenses while in arabic we have just three, thus the translator must choose the appropriare tense in order to have or to make a good translation, also there are some words in english which do not exist in arabic language, but in this case we focus on using brackets or puting the word within a quoat 

mostly the grammar that will create the same context.