Поставьте глаголы в тексте в отрицательную форму при отрицательной частицы not например: was-wasn't history and future of the internet he internet technology was created by vinton cerf in early 1973 as part of a project headed by robert kahn and conducted by the advanced pr research agency, part of the united states department of defense) later cerf made many efforts to build and standardize the internet an 10g4 the technology and the network were turned over to the private sector and to government scientific agencies for further development (the growth has continued exponentially service provider companies that make "gateways" to the internet available to home and business user enter the market in ever increasing numbers.

History and future of the Internet he Internet technology wasn't created by Vinton cerf in early 1973 as part of a project headed by Robert Kahn and wasn't conducted by the Advanced Pr Research Agency, part of the United States Department of Defense) Later Cerf didn't make many efforts to build and standardize the Internet. An 10g4 the technology and the network weren't turned over to the private sector and weren't  government scientific agencies for further development (The growth hasn't continued exponentially Service provider companies that make "gateways" to the Internet available to home and business user hasn't entered the market in ever increasing numbers.

  hey mark! what are you going to do during half-term ?

            you (won't believe) it but i(visited) swizerland !

            really ? that's so exciting ! swizrland is great. i'm sure   you (loved) it.

            i think so, too. my family and i (stayed) at a hotel near the swiss alps.

              wow

              yeah, it great.i (played) in the snow every day.my brother and i also ) to learn how to ski.

              you're so lucky.i wish i could go with you.

                maybe you can. (should i ask) my parents ?

                definitely!

                ok, then. i (will talk) to them tonight.

                    great!

                  i think we should go to class now or we (will be) late 

                you're right. let's go 

   Do NOT talk to the strangers when you play outside. 
Do NOT buy any food or drinks.
Do NOT scream or shout.
Do NOT turn on the music on your mobile or notebook too loud.

Ask other boys and girls to join you, if you see that somebody is not invited.
If there is a couch or another adult with you, listen to his/her attentively. 
If a stranger is asking you or somebody from your group to go with him/her somewhere or to have a ride with him/her, tell about it immidiately to the couch/teacher or call your parents.