A.When we are sure about what we are looking for, we will understand the whole human history.
B.No other culture is advancing as the human culture.
C.As long as the group forms a culture, they may have history,.
D.It will be impossible to find the beginning of the human history.

A.lack of interest in others.
B.self-centeredness.
C.unintelligence.
D.lack of social feeling.
A.help him correct the mistakes.
B.blame him for his ignorance.
C.leave him alone to work out the problem.
D.help him face the consequences bravely.
A.learning by himself.
B.cooperating with others.
C.thinking independently.
D.understanding the meaning of life.