【正文】 characters in different amusing situations” (Hornby, 2004).Sit originated in 1920s, the first sit was Sam and Henry which debuted in 1926 in America. And then, in the late 1940s, the sit had bee a new form of television.Sits often show the mon life of ordinary people in some mon environment such as home and workplace. Usually, the main characters are in some fixed locations and live their own lives. Each episode has a different theme, so the audience can feel the same joy and happiness as them. The sit is usually an indoor play with few outdoor scenes. Its usual formula is a bunch of friends getting together, including romantic relationship and friendship, and always with a happy ending. Laugh Track of Sits Laugh track is also called “l(fā)aughter soundtrack”, or “LFN” (laughter from nowhere). It is invented by Charles Douglass with the artificial sound of audience laughter.Sit is popular for its humor. To make the audience laugh is its most important factor and the ultimate goal. Because the success of a sit lies in whether it makes the audience laugh or not. In the past, there were only several people playing on the stage with a few audiences watching and laughing. Then after the invention of television, this kind of laughter is added as “l(fā)augh track”, which is the distinctive feature of sits. Then the effect of a live studio audience can be imitated by the laugh track naturally. The Hank McCune Show in 1950 first cooperated with the effect of the laugh track. The laughter is basically from those who watched in the studio when the show is filmed. Sometimes the producers of the sits would add some recorded laugh in order to get the desirable effect. Although some people criticize that this laugh track is fake and an undervaluation to the audience, the audience do not take it too seriously and will accept this effect if it is a good show, which is especially suitable for foreign audience such as Chinese audience, because it is an indication of humor. When foreign audiences do not understand the native humor, laugh track will be a good choice for culture and language learning. Features of Sits Sit is a special form of TV series which differs from other ones. Generally, each episode of the sit lasts about 20 minutes. It often happens in some certain places, such as dining room, living room or kitchen, and happens between friends or family. People get together talking about their lives or works. It remains in one place and has many lines circling on different characters in places like home and workplace. One episode from another is not very close, but it remains the coherence. General features of sitsThe essence of sit is humor. Humor is hard to define. It is a phenomenon that causes a laugh. In sits, there are both verbal and visual humors. The book Aspects of Verbal Humor in English describes sixteen modes of verbal humor in different writings on the subject of humor(Alexander, 1997:10). There are a lot of forms of humor occurring in sits, such as jocks, epigrams, puns, ironies, and parodies, etc. We can find humor in everywhere. We can find humor in our daily conversations, on televisions, in books, newspapers and magazines, etc. Almost all fields and places are filled with humor, whether it is family, school, work, television, sport, and economy, etc. Humor has so many positive significations that few words can equal. The meanings that humor carriers are optimistic, irony, amusing and funny, etc. The most important part in sits is humor, which makes sits attractive to audience. Humor is sits all about, and how to make audience laugh is what sits really matters. So the producers of sits would try their best to make people laugh.There are diverse characteristics in one sit. It deals with normal American life and culture edy. Sit characters are exaggerated and they are usually those typical Americans. Such as a lady’s man, women who only care about fashion or those boring businessmen. These classic roles can easily make audience back to their normal life and link the show with their friends. Because people would not treat sits as seriously as other TV series, generally, sits would be more boldly talking about those serious or controversial topics in American culture.There are a lot of classic sits such as: The Big Bang Theory, Friends, Two Broken Girls, Modern Family, How I Met Your Mother and Two and a Half Men, etc. The theme is often different from one sit to another. In The Big Band Theory, the story centers on five characters: Roommates Leonard and Sheldon, two prodigies in physics who work at California Institute of Technology, two equally smart friends Howard and Raj, and one attractive blonde beauty Penny whose aspiration is to bee an actress. In the classic sit Friends, it shows the daily life, love, happiness, and conflicts among six friends in the Greenwich Village area of Manhattan. The story mainly describes six good friends in New York City’s living together who experience a series of stories. It shows how they bee acquaintance in 10 year life. The stories describe life, trouble, the contradiction, love, the work and the friendship between friends, which resonates the audience’s emotion. In the sit How I Met Your Mother, Ted tells his children about how he met his wife, the show centers on the romantic stories between Ted, Marshall, Lily, Robin and Barney. This play is not only a humorous sit, but also rich in philosophy of life, which mixed with many practical factors, such as unemployment, contradiction between work and ideal life, the pain of lost loved ones and how to be optimistic towards life after some miseries. It is full of warmth and educational meaning. Language features of sitsFrom some highly used words and tones we can acknowledge that sits words are colloquial and humorous. Those sits are keeping up with the times and bearing the culture. Sometimes they have technical terms and selfmade phrases. Because informal language i