spend a lot of time
therein such places
The words "thus", "therefore", and the like, are more appropriate than "So"
As single sex schools have been the main education system
used to be in many countries all across the world fromsince many years ago,some people think that they are the best type of schools for children
They believe that students have more concentration on their studies in single sex schools.
WHY? Why do they think students can concentrate on their studies in these schools? Explain it and make it clear for the reader.
students who studied in co educational schools usually had many problems with the opposite sex.
What kind of problem? It is not apparent. u can make is more clear by using "such as".
have a better communication skills
with variety type of people in society
Because scientists believe
Never start a sentence with "BECAUSE". In Farsi it is OK, but in English it is WRONG.
in schools should
"Attending" is used with no preposition
"Evidence" is an uncountable noun and u cannot use it in plural form.
Personally I think that co educational schools could benefit our society in many ways and although there are a few problems in these schools, their pros far outweigh the cons of them.
This conclusion should be improved. At the beginning of the conclusion reword the thesis statement to remind the reader that u was discussing what issues in the body. Then write your opinion. Finally write and ending statement called clincher.