1.以 to do 開頭 To clean the classroom is our task this afternoon.
2.以 介詞+doing 開頭On hearing the good news ,we all jumped with joy.
3.以 doing 開頭Walking in the street,I met an old friend of mine.
4.以 done 開頭Seen from the top of the mountain ,the city looks very small.
5.以 having done 開頭Having finished the work ,they went home.
6.以 when/while doing 開頭when /while watching TV,we heard a cry.
7.以 when/while done 開頭when seen from the top of the mountain,the city looks very small
8.以 if/until/although/once/unless done 開頭各造一句
If untreated,the disease will become serious.
keep silent untill told to speak.
Although invited,I don't want to go to his party.
Once gained ,our friendship will get firm.
I will pick you up at the theatre unless told you won't come.
9.以 adj.或形容詞性短語(yǔ)開頭
10.以 連接詞+adj.開頭