根治原发性肝癌的最好方法是：（）
A.放射治疗
B.手术切除
C.免疫治疗
D.化疗
E.中药治疗
参考答案：B
The more one is ______ the English－speaking environment，the better he or she will learn the language.
A．exposed to
B．filled in
C．caught on
D．kept up
纯系
