PRACTICE: Underline the subject of the adverb clause and the subject of the main clause. Change the adverb clauses to adverbial phrases if possible.
1. While Joe was driving to school yesterday, he had an accident.
- While driving to school yesterday, Joe had an accident.
2. While Jim was watching TV last night, the telephone rang.
3. Since Ann remembered that she hadn't turned off the oven, her husband drove directly home.
4. Before the student came to class, the teacher had already given a quiz.
5. Since I came here, I have learned a lot of English.
6. Since Bob opened his new business, he has been working 16 hours a day.
7. After Omar (had) finished breakfast, he left the house and went to his office.
8. Alex hurt his back while he was chopping wood.
9. You should always read a contract before you sign your name.
10. Before the waiter came to our table, I had already made up my mind to order shrimp.
11. Before you ask the librarian for help, you should make every effort to find the materials yourself.
12. While Jack was trying to sleep last night, a mosquito kept  buzzing in his ear.
13. While Susan was climbing the mountain, she lost her footing and fell onto a ledge several feet below.
14. The Wilsons have experienced many changes in their lifestyle since they adopted twins.
15. After I heard Mary describe how cold it gets in Minnesota in the winter, I decided not to go there for my vacation in January.
16. While Sam was driving to work, his car got a flat tire.
17. While I was traveling across the United States, I could discover new places and people.
18. While we were enjoying the cool evening breeze and listening to the sounds of nature, we lost track of time.
19. Jane’s camera quit working while she was photographing a model this morning.
20. While my family and I were living in the Pacific Northwest, it rained a great deal.