~ Google tips ~

[HOUDA-K]

P hrase your question in the form of an answer. So instead of typing, "What is the average rainfall in the Amazon basin?", you might get better results by typing "The average rainfall in the Amazon basin is."

[DeltaAziz]

Salam

Using both give same result
Well the best way to write related words only
for your example, type "average rainfall Amazon Basin"
avoid using "the", "in" and "is"
you get the same result at 2nd rank