Если бы люди не мусорили было бы чисто

More important, the size of the dumpster. If often such a situation: it is filled, and the janitor fails to clean up, we need a more capacious.

Conclusion:
Convenient boxes any more — the city is still cleaner

We like to call people pigs, chant: "Purely not where clean and where don't litter". But I think the problem is not only in the people. I think differently:
Pure therewhere a lot of convenient boxes
The article is open for discussion. If you find a bug, think differently, and photographed an interesting case, feel free to contact. We will discuss and improve the article.
This post concludes a series about the design of ballot boxes. If you are interested in the theme — follow me on instagram, I am there every evening from 23 April 2015, publish the trash and comment. In the near future articles about the urns do not wait.
promision garbage

This school year we have visited many interesting places. - верно.
We have gone to the Excursion of the museum this month. - после глагола go только to 
It was interesting because there were a lot of beautiful pictures in the museum which we liked very much. - здесь не скажешь в Present Prefect
Also the museum guide has told us very interesting history about these famous pictures. - так тоже не говорят, но с точки зрения грамматики предложение построено верно.
We were happy because we have already gone to this excursion and have learnt a lot. - то же как и в предыдущем предложении, лучше было бы просто в Past, но раз задание только в Present Perfect, пусть будет так.
Best of all I liked waching the pictures which I have never seen before. - Больше всего мне понравилось рассматривать картины, которые я никогда не видела раньше.

- You had it, Ana! Did you remembered how I gave it to you so you could read it?- Jack sat down still having his eyes on Ana who was trying to find a paper that Jack gave to her last monday.
- I knew that I'm going to lose your paper, Jack... - she was saying while she was looking at her table - Oh, I found it !
- Ana, put it on your table. I just want to make sure that everything is okay to my papers - politely asked Jack.
- It was a terrible idea - said Ana, she got that paper and gave it back to Jack...
- You wrote pizza delivery phone number on it!? I told you that I'll sent to office in Mexico!? Pack your things, Ana! - said Jack, then he came closer and said softly:
-You have only 10 seconds to run away. GO!
Ana started running. She didn't want to go to Mexico.