Perfect tenses используются для описания, обозначения результата действия или явления, без точного обозначения совершения события to have + v3 present perfect tense есть результат действия к данному моменту + have v3 has ( 3л.ед.ч. - he,she,it) she has gone to work. we have played tennis. - have not v3 has ( 3л.ед.ч. - he,she,it) she hasn’t gone to work. we haven’t played tennis well. ? have v3? has has she gone to work? have we played tennis yet?

People do usually say that nature is our mother. It gives a person everything that is necessary for life, even though we don't always appreciate its gifts. What could be better than the warm sun, majestic mountains, and blooming trees in the spring? The world of nature is very rich and varied. There are hundreds of thousands of species, many of which we've never seen in our life.

We all used to live in a world that seems to be built by ourselves. We live in big houses equipped with high-tech consumer devices; we are able to travel long distances using cars, trains, and planes. We are able to know what is happening thousands of miles away, over the Internet or television. But all of this is secondary. We use the knowledge of the laws of nature and its power to create all these technologies anyway.

Cars burn petrol, factories burn coal and emit toxic fumes. The pollution is gathered in clouds that the winds carry far away. When it rains pollution lands on everything that surrounds us. This is called acid rain. Acid rain also gets into lakes, rivers, seas, and soil and pollutes everything causing serious damage. Fortunately, the governments have been trying to reduce the air pollution using new technologies. But we have to do more! but we need to do more. We can help reduce the amount of acid rain by using ours cars less or by using solar power to heat our homes.