We ______ ; we followed the boss into the hall as his guests. How lucky we were!
Human be haviour is mostly a product of learning, ____ the behavior of animals depends mainly on instinct.
_______ from the hill, the whole city of Nanjing looks more beautiful.
____ I saw her, I remembered to give Marie the money I owed her.
―Who are those people walking along the street with banners?―A group _______ itself the League for Global Environment Protection.
_____ human beings live in great numbers, the waters are very likely to become contaminated.