[单项选择]Psychologists agree that human beings have a strong need to ______ their time; having too much idle time can be as stressful as having none at all.
A. threaten
B. annihilate
C. structure
D. punctuate

[单项选择]The human beings have polluted the environment seriously. It is time the United Nations {{U}}must take{{/U}} some measures.
A. take
B. taking
C. to take
D. took

[单项选择]

Human societies have experienced so many wars, but have you ever thought about what a war really is War may be a natural expression of biological instincts and drives toward aggression in the human species. Natural impulses of anger hostility and territoriality are expressed through acts of violence. These are all qualities that humans share with animals. Aggression is a kind of innate survival mechanism or an instinct for self-preservation that allows animals to defend themselves from threats to their existence. But on the other hand human violence shows evidence of being a learned behavior. In the case of human aggression violence cannot be simply reduced to an instinct. The many expressions of human violence are always conditioned by social conventions that give shape to aggressive behavior. In human societies violence has a social function. It is a strategy for creating or destroying forms of social order. Religions have taken a leading role in directing the powers of violenc
A. Legal systems greatly reduce the possibilities of physical violence.
B. Offenses against individuals are no longer judged on a personal basis.
C. Victims of violence find it more difficult to take revenge.
D. Punishment is not carried out directly by the individuals involved.

[单项选择]Human beings have ______themselves to very diverse environments with the help of fire, agriculture and machines.

[单项选择]Human beings have ______ themselves to very diverse environments with the help of fire, agriculture and machines.


A. adapted
B. addicted
C. adopted
D. adhered