Find the names of courses taught by the tutor who has personal name "Julio".
SELECT T2.course_name FROM Course_Authors_and_Tutors AS T1 JOIN Courses AS T2 ON T1.author_id  =  T2.author_id WHERE T1.personal_name  =  "Julio"
names of courses taught by tutor = SELECT course_name; tutor who has personal name 'Julio' refers to WHERE personal_name = 'Julio'; joining tables refers to JOIN; matching tutor to courses via author_id.