单选题 Americans are more socially isolated than they were 20 years ago, separated by work, commuting and the single life, researchers reported.
Nearly a quarter of people surveyed said they had "zero" close friends with whom to discuss personal matters. More than 50 percent named two or fewer close friends, the researchers said.
"This is a big social change, and it indicates something that's not good for our society," said Duke University Professor Lynn Smith-Lovin. Smith-Lovin's group used data from a national survey of 1,500 American adults that has been ongoing since 1972.
She said it indicated people had a surprising drop in the number of close friends since 1985. At that time, Americans most commonly said they had three close friends whom they had known for a long time, saw often, and with whom they shared a number of interests. They were almost as likely to name four or five friends, and the relationships often sprang from their neighborhoods or communities.
Ties to a close network of friends create a social safety net that is good for society. Research has also linked social support and civic participation to a longer life, Smith-Lovin said.
The data also show the social isolation trend mirrors other class divides: Non-whites and people with less education tend to have smaller social networks than white Americans and the highly educated. That means that in daily life, personal emergencies and national disasters such as Hurricane Katrina, those with the fewest resources also have the fewest personal friends to call for advice and assistance.
"It's one thing to know someone and exchange e-mails with them. It's another thing to say, 'Will you give me a ride out of town with all of my possessions and pets? And can I stay with you for a couple or three months?'" Smith-Lovin said.
"Worrying about social isolation is not a matter of remembering a warm past. Real things are strongly connected with that," added Harvard University Public Policy Professor Robert Putnam. He suggested flexible work schedules would allow Americans to tend both personal and professional lives.

单选题 One reason for the social isolation of Americans is ______.
A. frequent relocation
B. frequent traveling
C. living alone
D. working flexible hours

单选题 The percentage of people with more than two close friends is about ______.
A. 25% B. 50%
C. 60% D. 75%

单选题 According to the passage, close social ties among people are ______.
A. a must for social progress
B. beneficial for the family
C. a source of happiness
D. good for people's health

单选题 It is implied that ______ tend to live a more socially isolated life.
A. people in the higher social ladder
B. people in the lower social ladder
C. people with a longer life span
D. people with a shorter life span

单选题 According to Robert Putnam, ______.
A. it is useless to worry about social isolation
B. social isolation is not necessarily bad for us
C. it is time to do something about social isolation
D. social isolation does not mean the end of society