Question: When did the financial crisis start in 2008?
qaPairs: question: On what date did the financial crisis of 2008 actually start happening?
answer: April 2007
question: Upon what 2007 event did the financial crisis of 2008 start happening?
answer: depreciation in the subprime mortgage market
question: On what date did the financial crisis in 2008 start developing into a full-blown international banking crisis?
answer: September 15, 2008
question: Upon what event did the financial crisis in 2008 start developing into a full-blown international banking crisis?
answer: collapse of the investment bank Lehman Brothers