напишите о ущербе и пользе мобильного телефона либо о будующих изобретениях

What do we know about the use and harm of mobile phones? I think mobile phones are very useful because at any time you can connect to any person you like. Besides this you can ask any questions and get answers at once. Mobile phones are very convenient in use. From year to year new functions are introduced.
On the other side children and elders make harm to themselves by listening music by ear phone and playing all kinds of plays. They may become short sighted or even damp. With the extention of mobile phones people read less books and they don't know much by heart.
I think everything must be in its measure and we must know when to stop.