I included my doubts in brackets. I really hope you can check them, too.
1)Mary uses the internet mainly to carry out school research in History, Geography and Science.
2)Whenever she needs to get (new) information/facts, she looks it up on the net.
3) It's quick and easy since she just has to type a topic (I don't know how to call it) in the search bar (I can't remember the name for it) and in less than a second she gets all the information she needs.
4) If she couldn't usethe net, it would take twice as long.
5) Samantha tried to use a translation programme on the net. She sent them the text and the programme translated it for her.
6) The translation wasn't very good and she didn't get good marks.Once she gets the facts she needs, she put them into her own words.
7) On the contrary, Mark downloads the information he needs from the net and uses it word for word (without changing anything).
8) Paul, on the other hand, (Can you suggest a better sentence connector) uses an online homework agency. He sends them his homework questions and they type him back the answers. He just has to hand them in to his teachers.
Google Search? for #3
4. spacing "use the net"
6. because you were using Present Tense, put = puts
Sra
1) Mary's main use of the internet is for school research in subjects like History, Geography, and Science.
2) When Mary needs to find new information or facts, she goes online to search for them.
3) To do this, she simply types a topic or keyword into the search bar of a search engine, such as Google, and within seconds, she gets all the information she needs.
4) Mary realizes that if she didn't have access to the internet, it would take her twice as long to gather the same information using other resources like books or encyclopedias.
5) In contrast, Samantha tried to use a translation program on the internet. She submitted her text to the program, and it automatically translated it for her.
6) Unfortunately, the translation provided by the program wasn't very good, resulting in poor marks for Samantha. Mary, on the other hand, avoids relying on automated translation tools and instead puts the information she finds on the internet into her own words.
7) On the flip side, Mark downloads information directly from the internet and uses it word for word without making any changes or additions.
8) In contrast to Mark and Samantha, Paul uses an online homework agency. He submits his homework questions to them, and they provide him with the answers he needs. Once he receives the answers, he simply has to hand them in to his teachers.
(Note: The above explanations are based on the information provided in the text. If there are any specific doubts or questions you have about the content, please let me know.)