Part 4

1 educational -> education 

2 will be participated -> will participate 

Part 5

1 ...why Freddy had dropped....

2 ...will be constantly tailored...

3 ...entering the contest....

4....left the car keys...

1. had been (by the time)

2. was found (in 1991)

3.  talking ( enjoyed)

4. have studied ( since)

5. affordable( fun and..)

6. cooperation( in)

7. irliterate

8. financially (more)