原发性肝癌肝内转移最常见的途径
A.肝动脉
B.肝静脉
C.淋巴管
D.胆管系
E.肝门静脉
参考答案:E
So far all cloned animals have suffered from some different serious disorders, _____ dying soon after birth. [ ]
A. many of which
B. many of whom
C. many of them
D. many of that
哪些事实能说明空气中含有下列成分:
空气中有氧气______
空气中有水蒸气______.