Part time job

I am currently working as an English assistant teacher for my part time job. The students I teach are K1-P6 which is about 5 years old to 12 years old. They are so adorable, but sometimes too energetic. I feel rewarding when students understands the new lessons, and become proactive. However, I sometimes have difficulties teaching students whose first language is not English. Not being allowed to use Japanese in class, I have to choose the easiest vocabularies to have the students understand what I am trying to tell. I guess time will solve this... just crossing my fingers that it would.