大肠癌最主要的转移途径是（）
A.血行转移
B.淋巴转移
C.直接蔓延
D.肠腔种植
E.癌细胞脱落
参考答案：B
From his _______ expression on his face, we know he is _______.
A．frightening, frightened
B．frightening, frightening
C．frightened, frightened
D．frightened, frightening
简述监护制度的发展阶段。
