I....has both advantages and disadvantages.……既有利又有弊。例如：
1.Obviously television has both advantages anddisadvantages.
2.Living in a city has both advantages anddisadvantages.
3.Com pared with cars，bikes have their advantages and disadvantages.
举一反三：
1.Although computers bring people a lot of convenience，they have many disadvantages.
2....has many advantages.For example，...However，justas every coin has two sides，...has its disadvantages.(本例将利弊分开讲，转折过渡自然。just as every coin has two sides也很值得背诵。)
II....play(s)an important role /part in...……在……中扮演重要角色/起重要作用。例如：
1.Computers play an important role in science andtechnology.
2.Computers play a more and more important role in ourlife. Computers play an increasingly important role in our studies.
3.Education plays an important part in developing ourmind.
4.Addiction to alcohol and drugs play a role inhomelessness.
举一反三：
1.Advertisement plays an informative role in our dailylife.
2.In the past，letters played a decisive role in long-distance communication.Butnow ，telephone，email，fax have taken their place.
III.With the development of...，随着……的发展，例如：
1.With the developm ent of our econo- m y，m any Chinese fam ilies can afford acar.
2.With the development of our economy and society，pollution is more and more serious.
3.With the rapid development of science and technology，people can get a college degree bytaking online-courses at home.
4.With the current social and technologicaldevelopments，employees withmore knowledge and higher academic degrees are needed.