阅读理解。
Until late in the 20th century, most Americans spent time with people of generations. Now mid-aged
Americans may not keep in touch with old people until they are old themselves. That's because we group
people by age. We put our three-year-olds together in day-care center, our 13-year-olds in school and sports
activities, and our 80-year-olds in senior-citizen homes. Why?
We live away from the old for many reasons: young people sometimes avoid the old to get rid of fears
for aging and dying. It is much harder to watch someone we love disappear before our eyes. Sometimes it's
so hard that we stay away from the people who need us most.
Fortunately, some of us have found our way to the old. And we have discovered that they often save the
young.
A reporter moved her family onto a block filled with old people. At first her children were disappointed.
But the reporter baked banana bread for the neighbors and had her children deliver it and visit them. Soon the
children had many new friends, with whom they shared food, stories and projects. "My children have never
been less lonely," the reporter said. The young, in turn, save the old. Once I was in a rest home when a visitor
showed up with a baby. She was immediately surrounded. People who hadn't gotten out of bed in a week
suddenly were ringing for a wheelchair. Even those who had seemed asleep wake up to watch the child.
Babies have an astonishing power to comfort and cure.
Grandparents are a special case. They give grandchildren a feeling of security and continuity. As my
husband put it, "my grandparents gave me a deep sense that things would turn out right in the end."
Grandchildren speak of attention they don't get from worried parents. "My parents were always telling
me to hurry up, and my grandparents told me to slow down," one friend said. A teacher told me she can tell
which pupils have relationships with grandparents: they are quieter, calmer, more trusting.
1. Now in an American family, people can find that ____. [ ]
A. children never live with their parents
B. not all working people live with their parents
C. aged people are supported by their grandchildren
D. grandchildren are supported by their grandparents
2. The reason why old people are left alone may be that ____. [ ]
A. the old don't like to live in a big family
B. the young can't get enough money to support the old
C. different generations have different lifestyles
D. the old are too weak to live with the young
3. The fact that the reporter told us shows that ____. [ ]
A. old people in America lead a hard life
B. old people in America enjoy banana bread
C. she had no time to take care of her children
D. old people are easy to get along with
4. Seeing a baby, the old people get excited because ____. [ ]
A. they had never seen a baby before
B. the baby was clever and beautiful
C. the baby brought them the image of life
D. the baby's mother would take care of them
CO2(g)十H2(g)十Q(Q＞0) CO和H2O浓度变化如下图，则0-4min的平均反应速率v(CO)＝______ 