September 11, 2001 is the day ______ we will never forget.
Flying kites, ______ some researchers point out, can not only bring about joy to us, but also promote our physical and mental health.
Your daughter would ______ a famous singer---she has a great gift for music.
The younger policeman was leaning ______ the wall with his arms folded when he heard someone for help.
One of the tourists ______ from the tour group. That was why the tour guide lost his temper.
______ we talk to each other, I feel happy.