query: SELECT avg(LifeExpectancy) FROM country WHERE Region  =  "Central Africa"
question: What that average expect life expectancy for countries in that region of Central Africa?
query_toks: SELECT avg ( LifeExpectancy ) FROM country WHERE Region = `` Central Africa ''
query_toks_no_value: select avg ( lifeexpectancy ) from country where region = value
question_toks: What that average expect life expectancy for countries in that region of Central Africa?