Usage of the first case of Russian nouns
（1） 做主语中做主语在电影.(For example:① Students are reading; ② There is a magazine on the table.)
（2） 做名次性合动营语的表语（For example: ①My sister is a teacher; ② Beijing is a beautiful and modern city.)
（3） 做同位语（例如: ①I really like ?October? magazine; ② My brother studied in the city of Krasnoyarsk.）
（4） 做呼语（例如: ①Guys, let's go to the cinema; ② Mom, don't wait for me for dinner.）