query: SELECT T1.address_line_1 FROM Course_Authors_and_Tutors AS T1 JOIN Courses AS T2 ON T1.author_id  =  T2.author_id WHERE T2.course_name  =  "operating system" OR T2.course_name  =  "data structure"
question: What-what being a address a a course author which what teaches either "a-operating a system" or "a data a structure" a course.
query_toks: SELECT T1.address_line_1 FROM Course_Authors_and_Tutors AS T1 JOIN Courses AS T2 ON T1.author_id = T2.author_id WHERE T2.course_name = `` operating system '' OR T2.course_name = `` data structure ''
query_toks_no_value: select t1 . address_line_1 from course_authors_and_tutors as t1 join courses as t2 on t1 . author_id = t2 . author_id where t2 . course_name = value or t2 . course_name = value
question_toks: What-what being a address a a course author which what teaches either "a-operating a system" or "a data a structure" a course.