—Jenny and Joe have________recently.
—How come?As far as I know,they have been good friends for many years.
A:picked up
B:made up
C:split up
D:given up
《百家讲坛》的学者易中天曾说过。“从孔子那里我读到( );在孟子那里我读到一股正气;从墨子那里我读到一腔热血;在韩非子那里我读到一双冷眼。”括号里填( )
①A∪B={1,2,3,4,5,6,7};②A∩B=∅;③A中的元素个数不是A中的元素;④B中的元素个数不是B中的元素.
若集合A含有2个元素,则满足条件的A有____个.