题干
Mary and Lily are good friends，and they love to sit by the seaside，________to each other for hours.
A：talking
B：to talk
C：having talked
D：to have talked
答案(点此获取答案解析）
A
(其中
为虚数单位，
)的实部和虚部互为相反数，那么
等于( ▲ )
