题目内容：
According to the passage，which of the following is TRUE?
A．Freedman and his colleagues hired 400，000 Americans to collect data． B．About four hundred thousand Americans worked for Freedman’s team full time for l3years．
C．People who took part in Freedman’s research are about 50 t0 70 Years old．
D．People who are 50 t0 70 years old seldom drink coffee·
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答案解析：