Writing prompt: How Can We Use Cellphones?

Student essay:
Cell phones have become increasingly popular in china these days. wherever you go you can see people using cell phones. many high school students have cell phones.
Cell phones have brought people a lot of benefits, but the most important is that they are convenient. with cell phones in their hands, they can keep in touch with anybody they want. if someone has a heart attack or a traffic accident, a call to emergency hospital or to the police can quickly bring him the help he wants.
However, cell phones can also bring people problems. the most serious problem is that when people are having a meeting or at a concert etc, the ring of the cell phone may interrupt others. so i think people should use cellphones as little as possible.

Corrected essay:
Cell phones have become increasingly popular in China these days. Wherever you go you can see people using cell phones. Many high school students have cell phones.
Cell phones have brought people a lot of benefits, but the most important is that they are convenient. With cell phones in their hands, they can keep in touch with anybody they want. If someone has a heart attack or a traffic accident, a call to an emergency hospital or to the police can quickly bring him the help he wants.
However, cell phones can also bring people problems. The most serious problem is that when people are having a meeting or at a concert, etc., the ring of the cell phone may interrupt others. So I think people should use cell phones as little as possible.