We all feel it is Jack as well as his wife that ________ for their son's bad performance at school.

A．are to blame

B．is to be blamed

C．are to be blamed

D．is to blame

符合黏液表皮样癌的声像图表现是（）

A.腮腺区可探及囊性病灶

B.病灶界限边缘不清，轮廓不完整，内部呈弱回声，囊性变时，可显示无回声区

C.病灶以液性回声为主，内部可见不均质低回声与致密较强回声交错分布

D.液性回声中出现致密较强回声团块

E.肿瘤如为高分化癌可见回声降低