过热蒸汽两侧温差最大不大于（）℃。
A、10
B、15
C、20
D、30
参考答案：C
肝血池显像中原发性肝细胞肝癌处血池放射性较周围肝组织为（）
A.增高
B.相似
C.较低
D.明显低
E.缺损
Not much people realize that apples have been cultivated for over 3,000 years.
A．Not many
B．Not enough
C．Without many
D．No many
