Historical clue formulations

• Spring break preceder, often — 2016-03-05
• Like half of all congressional elections — 2014-03-05
• Kind of exam, with a hint to the answers to the four starred clues — 2008-04-15
• Important exam — 2007-02-04
• Big test — 2006-12-24
• Student's worry — 2004-04-21
• College test — 1994-08-07