Technology provides us with numerous positive effects. Some people say that they are suffering from severe bad effects because of technology development.(why do you say so?) However, I strongly agree with the idea that we have received a lot of benefits from technology. People can live conveniently; technology enables us to live longer than one thousand years ago. (you shoud write two reasons at least but you've mentioned that just one reason. Also, it is not a good general idea)
To begin with, people can live conveniently. ( try to paraphase) Before people invented high technology, the world was full of inconvenience. For example, it took more than a month for a person to travel from South Korea to the America. Even two thousand years ago, there was no America. Columbus found the U.S with technology devices such as fast vessels and a telescope. (it is not a good supporting idea) In contrast, people can travel from South Korea to the U.S within a day these days.( thanks to the developement of the technology or something like that...) I have studied abroad from South Korea to the U.S. When I firstly got to here, it only took fifteen hours. (If you support your idea strongly, it is better to use a subjunctive sentence.)
On top of that, a person can live longer than two hundred years ago. (why do you say so?) Before technology was developed a lot, people could not help dying with diseases,(express another way) such as a cancer or leukemia. For example, I had one friend’s mother who suffered from a breath disease. (I had a friend with mother who was suffering from a breath disease.)Every her neighbors and friends was full of sorrows. They thought she would not live longer than a year. All of her friends took care of her, believing a miracle. (inappropriate), Suddenly, ( However, she could overcome the cancer went away from her body because of medical treatment and a surgery. Eventually, she recovered from the illness. She could not survive if she born in 1800s. I believe that not only her but also millions of people recovered from cancers because of technology development.
To sum up, I firmly support the opinion that technology gives people a lot of positive effects. First reason is that a person lives very conveniently; second reason is that technology development brought us longer lives.
(직장인이신데, 잘쓰신것 샅네요^^ 단 몇가지 (이 부족한 실력으로..) 코멘트 드리고 싶은 것은, 우선 명제가 불명확합니다. 명제를 서포트 하는 아이디어와 사례들도 좀 더 세련되게 다듬을 필요가 있을 것 같습니다. 이를테면 왜 그렇게 생각하는지...그에 대한 예로는 다음이 있다, 이런것들로 보았을때 내 명제가 이런것을 뜻한다...는 식으로 일련의 인관관계 형성 연습을 해보시는 것도 좋을 듯 싶습니다. 그리고 예들과 제너럴 스테이트 먼트를 설명하는 과정에서 부적절하거나 불필요한 예를이 있었습니다. 이를테면' 미국의 이동 시간이 줄었다는 얘기를 하는 과정에서 미 대륙 발견 얘기 같은 것이나...두 번째 단락 친구 어머니 얘기를 할때 주변 이웃들이 어떻게 생각 했는지 같은 것은 굳이 언급할 필요가 없는 문장에 속합니다. 글을 인과관계를 생각하시면서 좀 더 스트롱하게 쓰시는 연습을 해보세요^^)