No. of sentences 18
No. of words 308
No. of complex words 30
Percent of complex words 9.74%
Average words per sentence 17.11
Average syllables per word 1.43

Hi, Brian

Could you tell me how you counted the words of this essay? Using some softwares or……？Thank a million！

Would it be

Younger children benefit in particluar from constant guidance

Mary put the papers on her boss's desk.

is indeed a bit surprising

Nice to have you back Katiss, and thanks for this essay. It's fine. Brian has spotted a couple of things and made some good comments. 

Paragraph 4

You wrote

Moreover, watching TV is a passive way to spend time with no social interaction. While this point is not so much about computers, physical exercise and playing with other children are essential activities for a healthy development. Spending a lot of time in front of computer or TV screens limit’s a child time for such activities.

The phrase 'this point is not so much about computers' really stopped me in my tracks. I had to think about it and wonder what you were referring to. It's probably best to leave it out completely. Here's the paragraph with some minor rewrites:

Moreover, watching TV is a passive way to spend time. Physical exercise and social interaction such as playing with other children are essential activities for healthy development. Spending a lot of time in front of TV or computer screens limits a child's time for such activities.

(Watch out for those possessives and 's' -  verbs don't need apostrophes!)

Paragraph 3

Brian was a bit tough on you regarding your third paragraph. I thought it was OK, but I kind of get what he is saying.

You wrote:

Watching TV or using a computer can be addictive, even for adults. Parents must prevent their children from developing bad habits, like spending a lot of their time in front of the TV, early on. Not only should parents strictly limit their childrens'  screen time, they also need to be role models. Certainly, younger children will need more guidance, while teenagers can be given more responsibility in how they spend their time.

Maybe we can rewrite it so that the 'role model' idea comes earlier and the link or development is clearer:

Watching TV or using a computer can be addictive, even for adults. Rather than just limiting their children's screen time, parents need to be role models themselves and take part in different activities. Children from spending a lot of their time in front of the TV. Certainly, younger children will need more guidance, while teenagers can be given more responsibility in how they spend their time.

What do you think, Katiss?

Brian is right, though about 'especially' - it's better in the middle of a sentence, after the subject. There's advice here and here, but instead of worrying about it, I'd use 'in particular.' Or I'd rewrite the entire sentence.

Younger children especially benefit from constant guidance.

Short Sentences

Add a few short sentences. This will reduce the average length of your sentences (a bit high at 17.11), and a few short statements can be very effective. You have one already:

Watching TV or using a computer can be addictive, even for adults.

Other points

All things consideres ==> All things considered

Their childrens' screen time ==> Their children's screen time

So even if the content watched is age adequate and educational watching it for too long can be harmful for a child. ==> So even if the content watched is age-adequate and educational, watching it for too long can be harmful for a child.

Possessives, Plurals, and Apostrophes

Katiss - You seem to be puzzled by apostrophes and possessives! Find a grammar book or webpage and solve this problem for one and for all. An hour will clear it up for ever!

1. http://www.informatics.sussex.ac.uk/department/docs/punctuation/node22.html
2. http://grammar.ccc.commnet.edu/grammar/cgi-shl/quiz20.pl/plurals_quiz2.htm?cgi_quiz_form=1
3. http://www.eflnet.com/grammar/possessives.php  (not sure about question 7!

Basically, (1) if it's a verb, no apostrophe, (2) if it's a plural, no apostrophe, (3) if it belongs to someone, there's an apostrophe, (4) if it belongs to a group or a plural, there's an apostrophe, (5) if letters like 'i' or 'ha' are missing there's an apostrophe and (6) if it's a plural noun, no apostrophe.

1. A sensible parent limits (1) a child's (3) TV time.
2. The boys (2) were playing.
3. The children's (4) room is a mess.
4. It's (4) easy to understand.
5. The boy's (3) bicycle was stolen.
6. Children's (4) toys are quite expensive.
7. Parents (6) today have a lot of pressure.
8. The girls (6) are in the boys' (4) bedroom, cleaning up after their messy brothers. (6)
9. He plays (1) a lot of computer games (2) at his friends' (4) houses.(6)
10. He's (5) famous for his collection of CDs (6)
11. NGOs (6) such as Oxfam and the Red Cross help millions (6)
12. The United Nations' (4) headquarters (6) is in New York.
13. My sister's (3) very athletic. She's (5) run the New York marathon three times (6).
14. My uncles (6) are old men now, but my Uncle Fred's (3) world record for ice-skating still stands (1), and his brother Bill's (3) record for skiing was only broken ten years (6) ago. 

Due to I affraid of running time in IELTS exam I usually write under 300 (260-280)

It is generally accepted that spending too much time in front if the TV harms childrens’ development.Therefore, in my opinion parents should by all means limit their childrens’ TV and computer screen time, especially while they are younger.

It is generally accepted that spending too much time in front of TV has detrimental/harmful effects on childrens' growth. Therefore, in my opinion parents by all means should limit their chidlrens' access to TV and computer screen, especially in the early age.

Watching TV or using a computer can be addictive, even for adults. Parents must prevent their children from developing bad habits, like spending a lot of their time in front of the TV, early on. Not only should parents strictly limit their childrens'  screen time, they also need to be role models. Certainly, younger children will need more guidance, while teenagers can be given more responsibility in how they spend their time.

I cannot see much relevance on this paragraph. It souns that the main point you made is being addictive through watching too much TV. The rest of paragraph seems that did not well develope this idea as you mentioned about parents ' behavior. I guess you should decide what you are going to mention at this paragraph then deveope it. The probably paragrapg would be like this:

Watching TV or using a computer a lot can be addictive. It is very likely to see that those children spending too much time on watching TV or computer cannot give up this habits easily. Therefore, at the time of becoming parents, while their children their children need the guidance and advice, as they used to spend too much time on this activity could not fulfill their duties well.

Moreover, watching TV is a passive way to spend time with no social interaction. While this point is not so much about computers, physical exercise and playing with other children are essential activities for a healthy development. Spending a lot of time in front of computer or TV screens limit’s a child time for such activities.

I should say that the clarity of this paragraph is good. But I think your paragraph still to some extent vague whether you are going to say those activities  lack physical exercise social interaction. I think it would be better we avoid mix a couple of ideas in one sentence or paragraph.

Especially younger children can not concentrate for an extended time span without breaks.
Watching TV or playing computer games for many  hours can hurt their ability to concentrate on their homework or a book later on. So even if the content watched is age adequate and educational watching it for too long can be harmful for a child.

condentare on; their abilities, homeworks , educational, 

I am not sure about the structure of Especially younger used at the begining of the paragraph is a good one.( Hoping Mr Enda tells us).

Especially younger children should be guided to spend their time in active and healthy ways.

spend their time on active..

I hope Mr.ENda helps us in the fields I missed or made mistakes

It is generally accepted that spending too much time in front if the TV harms childrens’ development. Therefore, in my opinion parents should by all means limit their childrens’ TV and computer screen time, especially while they are younger.

Watching TV or using a computer can be addictive, even for adults. Parents must prevent their children from developing bad habits, like spending a lot of their time in front of the TV, early on. Not only should parents strictly limit their childrens'  screen time, they also need to be role models. Certainly, younger children will need more guidance, while teenagers can be given more responsibility in how they spend their time.

Moreover, watching TV is a passive way to spend time with no social interaction. While this point is not so much about computers, physical exercise and playing with other children are essential activities for a healthy development. Spending a lot of time in front of computer or TV screens limit’s a child time for such activities.

Especially younger children can not concentrate for an extended time span without breaks.
Watching TV or playing computer games for many  hours can hurt their ability to concentrate on their homework or a book later on. So even if the content watched is age adequate and educational watching it for too long can be harmful for a child.

All things consideres, there are many reasons why parents are well advised to monitor their childrens’ use of TV and computers closely. Especially younger children should be guided to spend their time in active and healthy ways.