Question

He started to playing the guitar in 1995.
--> He has 
People should improve all the schools and hospitals in this city.
--> All the schools
The principal's speech is interesting to the students.
--> The students feel
What a pity there isn't a big tree in my school.
--> I wishHe started to playing the guitar in 1995.
--> He has 
People should improve all the schools and hospitals in this city.
--> All the schools
The principal's speech is interesting to the students.
--> The students feel
What a pity there isn't a big tree in my school.
--> I wish

Answer 1

He started to playing the guitar in 1995.
--> He has played the guitar since 1995
People should improve all the schools and hospitals in this city.
--> All the schools and hospitals in this city should be improved 
The principal's speech is interesting to the students.
--> The students feel interested in the principal's speech
What a pity there isn't a big tree in my school.
--> I wish there were a big tree in my school

He started to playing the guitar in 1995.
--> He has played  the guitar since 1995.
People should improve all the schools and hospitals in this city.
--> All the schools and hospitals in this city should be improved 
The principal's speech is interesting to the students.
--> The students feel interested in the principal's speech
What a pity there isn't a big tree in my school.
--> I wish there were  a big tree in my school.