下列动物中具有冬眠习性，9℃以下即会出现冬眠的动物是（）
A、小鼠
B、大鼠
C、豚鼠
D、地鼠
参考答案：D
33．China has produced many great writers over the last ten years, Mo Yan.
A．among them was
B．among whom was
C．in which was
D．among whom were
“博士”的名称，源于（）
A．战国时代
B．五代时期
C．汉代
D．唐朝
