Verb has 2 senses

• drop back(v = verb.motion) - take position in the rear, as in a military formation or in the line of scrimmage in football; "The defender dropped back behind his teammate"

Sample sentence:
Somebody ----s

• drop back(v = verb.motion) drag, drop behind, get behind, hang back, trail - to lag or linger behind; "But in so many other areas we still are dragging"

Sample sentences:
Somebody ----s
Somebody ----s PP
Something ----s
Something is ----ing PP