11.   The series has been on TV every week for forty years.

12.   Try to set aside a few hours a week for exercise.

13.   This is orientation week for all the new students.

14.   It will take a few weeks for new employees to learn the ropes.

15.   His thinking was also stimulated by a medical student who came over once a week for dinner and lively chats.

16.   The latter was reported by the Sudanese News Agency to have gone to London the previous week for medical treatment.

17.   Fortunately he was on form the following week for shooting at White City stadium, in West London.

18.   Patients were reviewed every week for the first month and every other week until food reintroductions were completed.

19.   Although symptoms can be controlled in most patients it takes several weeks for maximal effect and prolonged relief requires higher radiation dose regimes.