Rewrite these sentence, using because
1  Most people hear jogging is a good exercise, so they begin to jog
2   A computer can be used for various purposes , so it becomes very popular nowadays
3 Our leader couldn't attend the meeting, so it was canceled
4  I always enjoyed mathematics in high schooll , so I decided to major it in college
Change clause of reason p phrase of reason 
1  We stopped our car because the traffic lights turned red
2   Piranhas can devour an entire cow in several minutes because their teeth are extremely sharp