Почему америку называют "mixed salad" или "melting pot"

The Great Melting Pot: Все разные, но в одном большом котле плавятся! 
Мозаика, чаша салата, калейдоскоп и плавильный котёл - метафоры, которыми часто называют Америку за то, что в стране слились воедино много разных национальностей и культур. Вместе они продолжают плавиться, и сливаться и объединяться. Название Melting Pot появилось ещё в 1908 году от названия одноимённой пьесы. И до сих пор так называют современное американское общество, так как и сами американцы считают, что  это единству всех живущих там народов разных национальностей, считать себя единой нацией -
народом одной страны, сохраняя в то же самое время и свою самобытность.
Но эта метафора не в состоянии отразить медленный, сложный и часто турбулентный процесс, посредством которого иммигранты различного происхождения и убеждений становятся частью американского общества и... преобразуют его.

Advantages and disadvantages of TV.
TV has good and bad sides. First of all it keeps people informed, we can learn a lot of information watching TV. We can choose programs that appeal to us more, because TV provides programs for all interests. Sometimes we can relax, entertain ourselves when we are tired. Advertisement on TV gives us information about different products and it makes easier to choose things to buy. When we watch TV we learn about the world, famous people and global or recent news.
But TV has a lot of disadvantages. It takes a lot of time and it makes us lazy. And it’s very harmful for our health, especially eyes. Some violent programs and films make people violent. Violence becomes a vital problem. There is too much advertisement on TV. Sometimes it can encourage us to buy things we don’t need at all. Watching TV takes most of free time of almost all people. We just watch it, we do not concentrate, and, finally, we waste time.
In my opinion people need something like informational center. As for me I watch TV about one hour a day. I watch it when I want to learn news or relax and entertain myself. People need TV, but it can’t be the main thing in their life. It’s interesting, but not the main thing in our life.
I don’t really know what we must do to make TV better. I think we can do nothing. We just should not sit hour by hour watching TV. I think we must watch only the most important and interesting things. Because if we see everything we’ll become mad.

I would like to tell you about the advantages and disadvantages of smartphones. We use our phones every day. It is thing we cannot live without in the modern century. Smartphones can serve also as a camera, calendar, planner and alarm. We keep in touch easily with our friends and family. You can send them pictures and videos. You can use a smartphone to watch funny videos, listen to the music or play your favorite games. If you have an emergency, you can quickly ask for help.

As for disadvantages, smartphones affect the nervous system and even damage your eyes. The social websites and games can lead to person`s addiction. Many people wake up in the morning and check their smartphones first. As you store a lot of personal information on mobile phones, you may have security risks, especially if you lose your smartphone. So you always must remember a correct password to protect all the information.