题目内容：

    Most of us are already aware of the direct effect we have on our friends and family. But we rarely consider that everything we think, feel, do, or say can spread far beyond the people we know. Conversely(相反地), our friends and family serve as conduits(渠道) for us to be influenced by hundreds or even thousands of other people. In a kind of social chain reaction, we can be deeply affected by events we do not witness that happen to people we do not know. As part of a social network, we go beyond ourselves, for good or ill, and become a part of something much larger.

Our connectedness carries with it fundamental implications(影响) for the way we understand the human condition. Social networks have value precisely because they can help us to achieve what we could not achieve on our own. Yet, social network effects are not always positive. Depression, obesity, financial panic, and violence also spread. Social networks, it turns out, tend to magnify(放大) whatever they are seeded with.

Partly for this reason, social networks are creative. And what these networks create does not belong to any one individual—it is shared by all those in the network. In this way, a social network is like a commonly owned forest: we all stand to benefit from it, but we also must work together to ensure it remains healthy and productive. While social networks are fundamentally and distinctively human, and can be seen everywhere, they should not be taken for granted.

If you are happier or richer or healthier than others, it may have a lot to do with where you happen to be in the network, even if you cannot recognize your own location. And it may have a lot to do with the overall structure of the network, even if you cannot control that structure at all. And in some cases, the process feeds back to the network itself. A person with many friends may become rich and then attract even more friends. This richget-richer dynamic means social networks can dramatically reinforce two different kinds of inequality in our society: situational inequality and positional inequality.

Lawmakers have not yet considered the consequences of positional inequality. Still, understanding the way we are connected is an essential step in creating a more just society and in carrying out public policies affecting everything from public health to the economy. We might be better off vaccinating(接种疫苗) centrally located individuals rather than weak individuals. We might be better off helping interconnected groups of people to avoid criminal behavior rather than preventing or punishing crimes one at a time.

If we want to understand how society works, we need to fill in the missing links between individuals. We need to understand how interconnections and interactions between people give rise to wholly new aspects of human experience that are not present in the individuals themselves. If we do not understand social networks, we cannot hope to fully understand either ourselves or the world we inhabit.

1.What can be inferred from the first paragraph?

A.We can't be easily affected by strangers.

B.We are connected and form a social network.

C.We have negative effects on other social members.

D.We will not make a difference in a specific group.

2.What does the underlined word “it” in the second paragraph refers to ?

A.something larger B.our connectedness

C.the human condition D.a social network

3.A social network can be compared to a commonly owned forest because ______.

A.it remains healthy and productive.

B.it tends to magnify negative things.

C.it is creative and shared by people in the whole society.

D.what it creates can be enjoyed by everyone in the network.

4.What's the author's purpose in writing the passage?

A.To introduce the characteristics of social networks.

B.To urge people to understand how our society works.

C.To show the significance of understanding social networks.

D.To explain the possible consequences of ignoring social networks.