Закончите предложения 1. … has served for almost 150 years as a key to discovering new elements and it has retained its key capacity until now. 2. His lectures were always listened to with great … 3. … began to write a great text book of chemistry, known in its English translation as "Principles of Chemistry" Hard work preceded it. Mendeleyev made thousands of experiments and calculations, wrote a lot of letters, studied many reports. 4. All those data were being brought together … 5. … earned him lasting international fame. 6. … were being brought together and grouped in a special way. 7. … serves as a basis for thousands of researches. 8. It is studied by philosophers, historians, teachers …

1.i see the plane in the sky.

2. a lot of factories polute our atmosphere.

3. sun is the biggest star in our galaxy.

4. people went to the moon in the 20th century.

moscow- the capital ofthe russian federation,federal city,the administrative center ofthe central federal districtand moscow region, of whichis not included.the appearanceof a city, as well asthe namesof manycities in the world,associated with the nameof the moskva river, whichborethis namelong before thesettlement.the oldestsettlementon the site ofmodern moscow,probably arosein those days,when they began todeveloptradeandcommercialrelationsbetween north and southof the russian plain.this was facilitated bymoscowlocationat the crossroadsbetween the balticdvinaandnemananddniepertothe uppervolga and thedon,the shortest routebetween themwasthe river valleysof moscowandklyazma.itwas foundedmoscow.

skateboarding is an action sport which involves riding and performing tricks using a skateboard

skateboarding can be a recreational activity, an art form, a job, or a method of trabsportation.skateboarding has been shaped and influenced by many skateboarders throughout the years

skateboarding is relatively modern. a key skateboarding maneuver, the ollie, was developed in the late 1970s by alan "ollie" gelfand as a half-pipe maneuver. freestyle skateboarder rodney mullen was the first to take it to flat ground and later invented the kickflip and its variations. since the 1970s, skateparks have been constructed specifically for use by skateboarders, bikers and inline skaters.

the current generation of skateboards is dominated by street skateboarding. most boards are about 7+1⁄4 to 8 inches (180 to 200 mm) wide and 30 to 32 inches (760 to 810 mm) long. the wheels are made of an extremely hard polyurethane, with hardness (durometer) approximately 99a. the wheel sizes are relatively small so that the boards are lighter, and the wheel's inertia is overcome quicker, thus making tricks more manageable. board styles have changed dramatically since the 1970s but have remained mostly alike since the mid 1990s. the contemporary shape of the skateboard is derived from the freestyle boards of the 1980s with a largely symmetrical shape and relatively narrow width. this form had become standard by the mid '90s.

go skateboarding day was created in 2004 by a group of skateboarding companies to promote skateboarding and help make it more noticeable to the world. it is celebrated every year on june 21.

the use of skateboards solely as a form of transportation is often associated with the longboard. depending on local laws, using skateboards as a form of transportation outside residential areas may or may not be legal. backers cite portability, exercise, and environmental friendliness as some of the benefits of skateboarding as an alternative to automobiles.