1. Ask students to read the following sentences and fill in the diagram. (PPT14)

☆ The underground system being built in the city will be open next year.

☆ Having seen the situation, a wealthy American businessman, Charles Yerkes tried to improve the system.

☆ Having been developed over many years, the underground system is now able to transport millions of people effectively.

被动进行式 主动完成式

被动完成式 Answers: being + done, having + done, having been + done

2. Ask students to rewrite the following sentences with passive and perfect forms of v-ing. (PPT15)

☆ It is said that the second line of Nanjing Underground is being built and it will reach Ma Qun.

☆ After the government has realized how serious the financial crisis is, it has been taking many measures to help people out of difficulty.

☆ After the plan had been revised many times, it was carried out last month.

Answers: ☆ It is said that the second line of Nanjing Underground being built will reach Ma Qun.

☆ Having realized how serious the financial crisis is, the government has been taking many measures to help people out of difficulty.

　　　　　☆ Having been revised many times, the plan was carried out last month.

3. Ask students to make right choice. (PPT16)

________ the differences between London Underground and Nanjing Underground, our government took some measures to improve the underground system.

A. Having compared B. Compared C. Having been compared D. being compared

Answer: A

　　Part four the subject of v-ing or v-ed clause

1. Ask the students whether we can rewrite the previous sentence into "Having compared the differences between London Underground and Nanjing Underground, some measures were taken by

our government to improve the underground system." If the students find it difficult to judge, the teacher can show another sentence and help them analyze the subjects of v-ing clause and main clause in each sentence. So that the students can make a right judgment and explain the reason. (PPT17)

☆ Having compared the differences between London Underground and Nanjing Underground, some measures were taken by our government to improve the underground system.

　　☆ Having been trapped in traffic, he was late for work.

Reason for the judgment: The understood subject of v-ing or v-ed clause is always the same as the subject of the main clause.

2．Help student use proper forms of words to fill in the blank with the help of the picture. (PPT18)

☆ _____ this public service advertisement, we think...(see)