Table: web_browser_usage_3
Columns: period
internet_explorer
firefox
chrome
safari
opera
other

Question: What internet explorer has 1.67% as the opera, with 2012 q1 as the period?
SQL: SELECT "internet_explorer" FROM web_browser_usage_3 WHERE "opera" = '1.67%' AND "period" = '2012 q1'

Question: What safari has 2012 q4 as the period?
SQL: SELECT "safari" FROM web_browser_usage_3 WHERE "period" = '2012 q4'

Question: What period has 53.52% as the internet explorer?
SQL: SELECT "period" FROM web_browser_usage_3 WHERE "internet_explorer" = '53.52%'

Question: What is the other that has 20.80% as the firefox?
SQL: SELECT "other" FROM web_browser_usage_3 WHERE "firefox" = '20.80%'

Question: What opera has 19.87% as the firefox?
SQL: SELECT "opera" FROM web_browser_usage_3 WHERE "firefox" = '19.87%'