— Where's your father?
— He ______ Beijing. He _____there last month.
A:has gone to; went
B:has been to; went
C:has gone to; has gone
D:has been to; has gone
“一战”对欧洲带来的影响有( )
①在十月革命影响下,欧洲许多国家走上社会主义道路 ②欧洲不再是世界格局的中心
③在世界上的财政金融地位急剧下降 ④在国际上的统治地位发生动摇
已知点Ma,ba>0,b>0是圆C:x2+y2=1内任意一点,点Px,y是圆上任意一点,则实数ax+by-1( )