Choosing the appropriate tense is the bigest difficult that the tronslator finds when translating from arabic to in English ? yes, No and justify?

No, I do not agree with that - it is difficult to choose an appropriate verb tense! I even do not see an issue here, because a translator does not need or required to choose. The work of a translator is to convey the meaning of the text with its all features, which entails using the same tense of the verbs used in the sources text.

kindly, the translator must convey the meaning existed in the subject or the text with all features using the tense of the verbs

I agree with Amir Ageeb completely. 

Yes you are right   when you use any  google translator but  you can get help from  any  translators