What are the advantages and disadvantages of using cellphones?

Thank you Se [이름]!

~Teacher Lucy

When I was young, students who have a cellphone are rare and especially elementary students.

>>When I was young, students who have a cellphone are rare and especially for elementary students.

But, it is not special and most of them have smart-phones.
>>CORRECT!
Thanks to popularization of cellphones, people receive many benefits.
>>CORRECT!
Before I have a cellphone, I used to find a public telephone station to call my mom and I need some coins to call her.

>>CORRECT!

 But now, I don’t need to do that.

>>CORRECT!

 Also, I can search everything anywhere not to ask someone.

>>CORRECT!

Because I have a cellphone which was small as the size of hand.

>>CORRECT!

Using cellphones make ours more convenient.
>>Using cellphones make us more convenient.
 However, it also have a bad effect to ours.

>>However, it also have a bad effect to us.

Although it is increased time to use a cellphone, it is decreased time to meet with people.

>>Although, it increased users of a cellphone, it decreased time to meet with people.

It make a society which don’t have a conversation.

>>It makes a society not to have a conversation.

 People felt to be isolated.
>>CORRECT!
The society should develop more and more and also watch and improve a side effect.

>>The society should develop more and also watch and improve the side effects.