Раскройте скобки, употребляя глаголы в соответствующем времени групп simple, continuous и perfect страдательного залога. 3 by six o’clock yesterday the work (to finish 4 he often (to invite) to our parties.

3 By six o’clock yesterday the work had been finished.-Past Perfect Passive
4 He is often invited to our parties-Present Simple Passive

Today our planet Earth is facing an important problem - the global warming. It occurs because of emissions of toxic gas and increasing greenhouse effect.
Polluting gases are exhausted by factories, cars and other machines. These gases pile up in the atmosphere and don't let the light reflected from Earth's surface get out of atmosphere, which actually causes the warming itself. Because of it, glaciers melt rapidly, the ocean level rises and that poses a flood threat to all islands and seaside countries. It also means an dramatic increase in number of icebergs in oceans, which basically means a threat to sea travellers. Which in its turn poses a threat to economies of a lot of different countries, since most goods are exported and imported by water trade.

Warming is also dangerous for nature since many species of plants and animals are used to live under low-temperature conditions. And if temperature goes up, then certain plants, which are actually food for animals, will die. And that in its turn will make animals starve, and then eventually die as well. And so will die animals, whose food was primarily the previously mentioned animals, and so on and so forth.

I want to live in a country with strong economy, rich flora and fauna and not-overly-hot climate!

Let us save our planet together!

Let us say 'NO' to atmosphere pollution!

Let us switch to alternative sources of energy!

Let's revive our forests!

All the rules, POZhALUYSTAStoit say that in the US today there are at least 200 uninhabited citiesso-called ghost towns. Colorado and California, Arizona and Montana, New Mexico and Nevada, Idaho and Utah tourists can show up to two dozen such sites. Their eerie appearance attracted mystics and filmmakers, as well as groups of tourists. The famous movie "Silent Hill" created in the image of abandoned cities in America. The city where there is a church and a school, and the telegraph station, shops and houses, but no inhabitants ... Each of ghost towns have their own tragic story.
"Oh My God!" - Exclaim tourists during excursions through the deserted streets. once, life in these cities was in full swing, and now only emptiness and silence. Most often, ghost towns are located in the United States of its central part, away from the major routes, gas stations. Sometimes, the cause is the depletion of natural resources, or any natural disasters, but more often they disappear on ordinary stupidity of the people themselves.
For example, the town of Cordes in Arizona was founded in 1883. After 12 years, lived there more than 400 people, and in 1926 it was already a real center, with beer bars, churches and shops. And in 1955, the city closed coal mines and local residents began to leave him. In the city of Centralia burned coal mines that can not be put out more than 40 years.
US ghost towns
Another story from the ghost town of Mokelumne Hill, located in California. It arose spontaneously, as a result of the gold rush, and in 1848 it has a population of 12 thousand people. It was one of the most violent cities, during its history have been killed and more than 39 sheriffs thousand inhabitants.
The fate of the doomed ghost towns - it is only slowly disintegrate and disappear someday. Although there are cases when these cities are national monuments and heritage of the country
For each of the American ghost towns can talk endlessly. And every ghost town keeps a lot of secrets that have yet to unravel ...