How many times did the word pair "i" and "a" appeared in the Cataln language/page?
times appeared refers to occurrences; word pair "i" and "a" refers to w1st.word = 'i' w2st.word = 'a'
SELECT SUM(occurrences) FROM biwords WHERE w1st = 86 AND w2nd = 109
database name:db_id language_corpus
langs table langs Cols: language id dtype integer, language dtype text, locale dtype text, pages dtype integer, words dtype integer, 
pages table pages Cols: page id dtype integer, language id dtype integer, page dtype integer, revision dtype integer, title dtype text, words dtype integer, 
words table words Cols: word id dtype integer, word dtype text, occurrences dtype integer, 
langs_words table langs_words Cols: language id dtype integer, word id dtype integer, occurrences dtype integer, 
pages_words table pages_words Cols: page id dtype integer, word id dtype integer, occurrences dtype integer, 
biwords table biwords Cols: language id dtype integer, word id of the first word dtype integer, word id of the second word dtype integer, occurrences dtype integer, 
