3. In a dark room, a drawer contains socks of two colors and two sizes, 4 pairs in total (one pair of each color and size). How many socks must be taken out to ensure that there are two pairs of different colors and different sizes?
New $A_{1}, A, B, B$ each two. Period out 6 as $A ., A_{1}, 1, B_{1}, B_{1}, B_{2}$, does not meet the question's requirements. But when any 7 are taken out, there must be one color (let's say A) with 4 pieces all taken out, and among the 3 pieces of another color, there must be two.