—When I first got to Harvard, my awkward English brought me great trouble.
——Oh, dear, it _______a struggle for you to keep up with other students.

—I visited China year.
—That          interesting.

-- Do you still remember when we went to Nanjing?
--- I can’t remember now but _________ sometime last summer?

About six years ago，I was eating lunch in a restaurant in New York City    36    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，    37    have you been？”And the boy，who    38    more than seven or eight years old， 39   ，”To tell you the truth，I’ve been feeling a little depressed（ 忧郁）lately．”

His words   40  in my mind because it confirmed my growing belief that children are changing．   41   I can remember，my friends and I didn’t  find out we were“depressed”    42 we were in high school．

The evidence of   43   in children has increased steadily in recent years．Children don’t  seem 44    any more．Children speak，dress，and behave more like adults than they used to．

   45   this is good or bad is difficult to say，but it certainly is different．Childhood   46   it once was no longer exists．Why？

Human development is based not only on born biological states，but    47    patterns of access to social knowledge． Movement from one social role from another usually involves learning the secrets of the new status．Children have always been taught adults’    48    ，but slowly and in stages: traditionally，we tell the sixth graders things we keep   49    the fifth graders．

In the last thirty years，  50   ，a secret - disclosing machine called television   51   installed in 98 percent of American families．It passes information， and indiscriminately（不加区别地），to all viewers alike，without considering they are children or adults．Unable to resist the temptation，many children    52    their attention from printed texts to the less challenging，more vivid moving pictures．

Communication through print，as a matter of fact，    53    a great deal of control over the social information   54     children have access．Reading and writing involve a complex code of symbols that must be memorized and practiced．Children must read    55    books before reading complex materials．

It isn't cold enough for there ________ a frost tonight, so I can leave his car out quite safely.

1. A.
   being
2. B.
   to be
3. C.
   having been
4. D.
   were