Thank you very much for helping me.
Here are some more sentences on the same subjects.
1)An electrician is someone who plans electrical equipments (systems, appliances??).
2) A nurse is someone who takes care of sick people.
3) A teacher is someone who provides young people with an education. (gives them an education)./ is someone who teaches his/her students.
4) A doctor is someone who cures (better: treats?) sick people.
5)We won’t start (have is possible?) until your dead arrives. He’s been working on an assembly line for three years.
6)I’m tired of this place. The architect Wren took 38 years to build the cathedral and he was buried there. 7)How long have you know Peter? How long is it since you have known (??) Peter?
1. systems
3. teaches his/her students
4. treats sick people
5. I think you mean this, "We won't start until your dad arrives." Right?
6. comma after "cathedral"
7. You need "known" in both sentences.