In the small towns of the United States in the   1        (nineteen) century, the general store was   2       everyone bought the things he couldn’t make     3          grow at home. What the stores sold   4       (tell) a great deal about   5         life at that time. People bought tools that they needed for farm work; salt, sugar and  6       foods that the farm didn’t produce; articles of clothing that they couldn’t make    7     ; shirts for the men; or clothes for the children. Life was simple then. One feels that people were   8      (thank) for what they had and that they looked  9      with courage to whatever the future brought. It would be interesting to know how they would feel about the life today. Would it seem to them that life is too complex? Would they enjoy   10    (live) a life as we do now?

皮内注入结核菌素后经多长时间观察结果

A．12～24小时

B．24～48小时

C．3～4天

D．48～72小时

E．4～5天