Read the rules and the examples. then make sentences. we use this/these for things near us. we use this in the singular and these in the plutal. we use that/those for things far away from us. we use thar in the singalar and those in the plural

you mustn't open the door for a stranger. a stranger should trick you. you might answer the phone. you don't have to tell everybody that you are home alone . you must know your parents' phone number. it have to be wise to know your neighbours .

advertisement plays a big role in our lives. some people don't like to see it everywhere and some people don't care about it. as for me, i think that  advertisement is an inportant part of our world. to keep the economy up we have to sell goods to people but it would be inpossible to sell a lot of products without advertising it. but i believe that it should be limited. i can't stand when i am in museum or theatre or any other cultural place and there i see commercial everywhere around me. i also don't like when i watch an interesting movie and it is interrupteb by a commercial. so my opinion is that the advertisement should have a right to exist but it should be limited.