SPT examples:

(+)  Erick and Erin walk in the park every morning at 8:30 a.m.
 (-)  Erick and Erin dont´n walk in the park every morning at 8:30a.m.
 (?) Do Erick and Erin walk in the park every morning at 8:30a.m.?
  yes   Yes, they do.
 (?) Do Erick and Erin walk in the park every nigth at 10:00p.m.?
  no     No, they don´t.