Though I have often heard this song _______. I have never heard you _______ it.
The teacher began by _____ us where the city was and went on ______ about its history.
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.