Question: Is the start time before 1991 for the Summer Olympic Games that follow the 1968 Summer Olympics?
Choices: yes
no
unknown
unknown
unknown
unknown
unknown
unknown
unknown
unknown
SPARQL: ASK { ?e <pred:instance_of> ?c . ?c <pred:name> "Summer Olympic Games" . ?e <follows> ?e_1 . ?e_1 <pred:name> "1968 Summer Olympics" .  ?e <start_time> ?pv . ?pv <pred:year> ?v . FILTER ( ?v < 1991 ) .  }
Program:
function: Find
inputs: 1968 Summer Olympics
function: Relate
dependencies: 0
inputs: follows
backward
function: FilterConcept
dependencies: 1
inputs: Summer Olympic Games
function: QueryAttr
dependencies: 2
inputs: start time
function: VerifyYear
dependencies: 3
inputs: 1991
<
Answer: yes