— I'm waiting for my friend. If he_______, I________ swimming alone.
A:doesn't come; will go
B:won't come, will go
C:will come, won't go
D:don't come, will go
(Ⅰ)求乙投球的命中率p;
(Ⅱ)若甲投球1次,乙投球2次,两人共命中的次数记为ξ,求ξ的分布列和数学期望.
设O是原点,向量OA→、OB→对应的复数分别为2﹣3i,﹣3+2i,那么,向量BA→对应的复数是____