I hear you have got a ticket ____ the Opening Ceremony of the Beijing Olympics. — Yes, I got it ____ my uncle. [ ]

To save the drowning child, the boy plunged into the icy water without hesitation, ____ his own safety.

Do you know ______ girl who is standing under ____ tree?— Of course! She is Lucy, my classmates.

You will find ______ useful to learn even a little English.

Before I talked with ______ scientist, I had never met_____ clever person like him.