单选题：Questions are based on the following passage. 　　About six ye

Questions are based on the following passage. 　　About six years ago I was eating lunch in a restaurant in New York City when a woman and a young boy sat down at the next table, I couldn’t help overhearing parts of their conversation. At one point the woman asked: “So, how have you been?” And the boy—who could not have been more than seven or eight years old—replied. “Frankly, I’ve been feeling a little depressed lately.”
　　This incident stuck in my mind because it confirmed my growing belief that children are changing. As far as I can remember, my friends and I didn’t find out we were “depressed” until we were in high school.
　　The evidence of a change in children has increased steadily in recent years. Children don’t seem childlike anymore. Children speak more like adults, dress more like adults and behave more like adults than they used to.
　　Whether this is good or bad is difficult to say, but it certainly is different. Childhood as it once was no longer exists, Why?
　　Human development is based not only on innate （天生的） biological states, but also on patterns of access to social knowledge. Movement from one social rote to another usually involves learning the secrets of the new status. Children have always been taught adult secrets, but slowly and in stages: traditionally, we tell sixth graders things we keep hidden from fifth graders.
　　In the last 30 years, however, a secret-revelation （揭示） machine has been installed in 98 percent of American homes. It is called television, Television passes information, and indiscriminately （不加区分地）, to all viewers alike, be they children or adults. Unable to resist the temptation, many children turn their attention from printed texts to the less challenging, more vivid moving pictures.
　　Communication through print, as a matter of fact, allows for a great deal of control over the social information to which children have access. Reading and writing involve a complex code of symbols that must be memorized and practices. Children must read simple books before they can read complex materials. According to the author, feeling depressed is ________. A．a sure sign of a psychological problem in a child
B．something hardly to be expected in a young child
C．an inevitable has of children’s mental development
D．a mental scale present in all humans, including children