Hi Minh Trang,
In general you have known how to write a decent essay, which was reflected in the clear arrangements of your ideas, the combination of the simple and complex structures, the correct use of linking words, etc.
As a reader, I think you should make some minor alterations in order to convince the readers more:
1/ The fourth paragraph where you discussed the negative points should be made the first one. Mentioning the shortcomings before the benefits will highlight the benefits more. (this is called "counter-argument" I think you've heard of it before)
2/ There are a few mistakes in word choosing and structures:
Recently, our society is witnessing an increasingly relevance of computers in education which gives rise to an inconclusive discussion about whether this modern technology is beneficial or harmful to children in study and life (this sentence is quite lengthy. You should shorten it by rephrasing "...about its benefits and drawbacks). To my best of knowledge, computers are wonderful devices in terms (Terms, plural form) of entertaining and educating children through many useful applications they offer.
First of all, a wide range of means of entertainment are always available in computers giving children eye- popping (informal, incorrect collocation) opportunities to relax. Playing games after a hard working day at school seems to be (sounds not convincing. Use a more emphatic phrase like "certainly is") a great delight for a child. For instance, children can be engulfed (I don't think this is a correct word. "Engulf" means "to overwhelm". You can simly use "derive pleasure from") in pleasure and relaxation when wining one level in chicken invaders. Thus, children can feel relief after learning. (this sentence is not necessary)
Equally important, computers orientate children to be decent citizens. A great number of moral lessons are easily to be obtained by children when they are illustrated by (with) vivid images and videos stored in computers. These visual tools can attract children’s attention easier than books or other materials. A beautiful and long lasting friendship between piglet and pooh bear in the cartoon “the Pooh bear” helps children to have(kindle in children) right attitudes towards friendship as well as other personal relationships. Therefore, computers play an important role in forming children’s dignity.
Computers have some drawbacks, however. Spending too much time sitting in front of desktop screens to watch films may put children under the threat of contracting some dangerous diseases (defects) like short – sighted(better use "optical impairments) or vertigo. In addition, accessing to misleading information in computers such as violence or terrorism (terrorism on the Internet? I don't think there is :|) may affect badly (badly affect sounds more natural) children’s thinking and personality.
In conclusion, I would agree that computers remain ("remain" means "continue to exist")some disadvantages. Nevertheless, their advantages have outweighed their drawbacks since computers help children relax and develop exemplary behavior.
