1．[2017·湘潭]Cao Yinpeng is a 9yearold Chinese boy. He is known ________ saving his father's life.
A．for B．at C．by
2．[2017·长沙] ________ April 22nd, people around the world celebrate Earth Day in different ways.
A．In B．At C．On
3．[2017·怀化]—What time do you usually get up on weekends?
—I usually get up ________ 7：00 o'clock in the morning.
A．at B．in C．on
