Is teaching science or French language, should be depending on the grade?

There is no limitation of age when it comes learning, children who are taught languages and simple science at early ages are the ones who grasp it more effectively and also remember it over the longer course of time

 The most successful way is to vary methods and techniques as much as you can. Just make sure it is the right decision by considering the learners, their level  of french and their 

interests 

I think a good teacher should  deal with all levels ( matter of relationship with the student and how to make him understand the questions) but when it comes to informations, you can't give what you don't have. If u have a high level of education you must answer every question you can, but if not... then you just can't so yeah it depends on degree

some arabic@ english but bangali is better

yes of course not all teachers are talented i mean a good teacher must be like a library to his students but in the same time he has to deal with all levels no matter how big is the information all students must understand the message well thus i think it all depends on experince