7.某人用步枪射击目标5次,A1表示"第i次射击击中目标" (i=1,2,3,4,5). B1表示"5次-|||-射击中击中目标i次" (i=0,1,2,3,4,5). 用文字叙述下列各事件,并指出各对事件之间的-|||-关系:-|||-(1)UA1与UB1;(2)U A1与UB1;-|||-2 :2-|||-(3)☆A1与UA1;(4)与-|||-^5(B)_(1);-|||-(5)UB1与 B13-|||-(6)A1A2A3A4 A5与B3;-|||-(7)A1与B5;-|||-(8)∪A1与B5·-|||-i=1