The work is an important link which in the teaching links the preceding with the following, this is well known.

The paragraph as a connecting link between A and B is important.

Youth is the most important part of life, it has the role of linking the role of, sum up his childhood, and childhood good-bye;

His Republic theory also has made a deep impression in the history.

Theme plays an important role in the process of text construction, and rheme is very important in transmitting new information.