志愿者精神是：“奉献”。还有（）
A.友爱
B.进步
C.互助
参考答案：A, B, C
23. A salty diet may increase the risk of stomach cancer ________ 10 percent, South Korean researchers found in a study of more than 2 million people.
A．at
B．to
C．by
D．For
