Порівняти яка з речовин містить більший вміст оксигену : Барій оксид чи Плюмбум (2) оксид

-our organise wants to   protect the environment.

-we fight against water and air    pollute

-are you unhappy with the ecological situate  in your region?  

-send us some inform about it and we`ll try to help. 

  one day in the summer one woman went into the forest and saw a small pond.she decided to look around him, because they had never pond on the site are not seen.as soon as she came unto him, hear the sounds and cries.the woman blinked away from the pond, and then i realized that she must help the people there who scream and ran to the pond.  she went right with the flow and soon found that there where she is beginning to emerge of a more of her or who have not seen and since then the myth of the woman..  people, don't be so gullible water

future – one of the strongest magic words in the history of humanity. from old times people began to ponder upon their future. sometimes ill-omened sometimes hopeful but it always attracted the human thoughts. there were many clairvoyants being engaged in predicting the future and very often there was nothing but pessimistic ways in their conclusions. and many times our civilization really stood on the edge of total wreck but heavens and just ordinary people by their efforts allow our planet to survive. but now standing on the boundary of the centuries and considering all the circumstances concerning with the problems of interrelations between countries, threat of ecological catastrophe, possibility of the beginning of the third world war, especially in the light of the events in yugoslavia, we cannot be sure that and this time any miracle will save the humanity from disaster.                but diverting from such pessimistic thoughts let me imagine our future concentrating on the aspects of developing and applying new technologies.                a few words about the space. i guess that cosmology will make a great strides in the near future. there will be a good possibility of inventing the light speed engine for the space vehicles or using the directed emission of the elementary particles but even otherwise i'm sure that the human civilization will spread its influence at least on the now known expanses of the universe. we will settle our colonies on the various planets and who knows whether on the earth there will be the centre or if you want the capital of mankind. maybe on these planets we will find the remains of old civilizations and use their knowledge and technologies for our needs. or, it's also possible, we will disturb any martial people and our civilization will be erased from the face of the universe. who knows? eventually, still sallusty said: “all that come into the world doomed to death”. 

1. since when have we  been friends?

2. has the rain  stopped?

3.how long has  the film  been?

4. had he  recovered by the time i returned from my leave?

5.how long will he  have worked as a teacher  by next september?

6. who will have started the discussion by the time you come?