1. The teacher always welcomes new students

=> New students are always welcomed by the teacher

2. People speak English all over the world.

=> English is spoken all over the world

3. Thomas Edison invented the phonograph in 1877

=> the phonograph was invented in 1877 by Thomas Edison

4. The police found two children in thw forest

=>  Two children were found in the forest by the police

5. They will send your oder as soon as possible 

=> your order will be sent as soon as possible

6. The scientists are studying the problem carefully

=> the problem is being studied carefully

7. Pat Murphy was riding the robbers

=> the robbers were being ridden by Pat Murphy

8. The police have just arrested the robbers

=> the robbers have just been arrested by the police

9. Sue told us she had born her baby

=> we were told that her baby was born 

10. They can use this room after 5p.m

=> this room can be used after 5p.m

11. They are cutting the cake with a sharp knife

=> the cake is being cut with a sharp knife

12. The children looked at the animals with strange eyes

=>  the animals were looked at by the children with strange eyes

13. They have provided the victim with food and clothing 

=> the victim has been provided with food and clothing

14. People speak English every where in the world 

=> english is spoken every where in the world

15. You must give this machine back before 5:30 p.m

=> this machine must be given back before 5.30pm