On what dates did the student with family name "Zieme" and personal name "Bernie" enroll in and complete the courses?
select t1.date_of_enrolment, t1.date_of_completion from student_course_enrolment as t1 join students as t2 on t1.student_id = t2.student_id where t2.family_name = "Zieme" and t2.personal_name = "Bernie"