11.   The next day, the Tour ran on schedule, with most of the riders not wearing helmets.

12.   They are holding automatic rifles and wearing steel helmets.

13.   They wore helmets suggestive of the heads of flies, and their black silks were embroidered with arcane silver hieroglyphics.

14.   Wearing a helmet reduces the risk of head injuries.

15.   Wearing a helmet when riding a motorcycle is mandatory.

16.   Why did she not wear her helmet, as she usually does?

17.   You are trying to police without wearing helmets.

18.   Wearing a helmet reduces the risk of head injury.

19.   ...the validity of making children wear cycle helmets.