A:excite
B:exciting
C:excited
D:excitement
He has two sisters. One is a doctor and is a teacher.
欣赏下面的漫画《堵》,材料说明了( )
集合A={x|x=a1×103+a2×102+a3×10+a4},其中ai∈{1,2,3,4},1≤i≤4,i∈N,则满足条件:ai中a1最小,且a1≠a2,a2≠a3,a3≠a4,a4≠a1的概率为( )