In conclude, I think that cell phone is very useful but you should not adsorb in them anymore and you should use mobile phone where is suitable which in the classroom was not suitable. You may switch off cell phone during class. Other than, you and friends don't lost concentration and everyone can absolute learning. So, you should grab a lot of knowledge that you received because there are much time to use mobile phone, on the other hand, there are few time to study. It just has in the classroom only / I had to studied this course again in next term you should pay attention to learn which it is best for you when you are in the classroom