1-After he ................the questions, he began to answer them.

2-When he...............the invitation, he decided to attend the party.

3-After the class.................., the students were allowed to enter.

4-After................. his homework, he decided to go out.

5-When I.................the station, the train had already left, so I missed it.

6- He had finished his work before he.................. a decision to watch a film.

7- ..............broken my ankle, I couldn't complete the game.

8-.................polished, the office seemed to be new.

9-...............seeing the policeman, the thief ran away.

10- She didn't clean the room till the guests...................

11-She didn't attend the party till she..................

12-The thief ............ till he had paid all his bills.

13-Please, remember to take your books before..................

14-No sooner had he gone shopping...................it began to rain.

15-..................had he reached Alex. when he was asked to return back.

16-Shortly...............meeting him, i realized that he was your assistant.

17-Immediately..............finishing my work, I slept.

18-It was only..............he phoned me that I realized he cancelled his appointment.

19-It wasn't ...........he had read the question that he began to answer.

20-Ther is a speed limit. You..............exceed it.

21-The corridor is dirty. You...............it now.

22-It's a ...................... to leave early or you will miss the bus.

The immortal Nile is life artery in Egypt, so we mustn't pollute its sweety water so as not to face  water shortage problem.

Increasing production and rationalizing consumption are ways to overcome our economic and social problems.