动脉瘤样骨囊肿的特征性MRI表现为()
A.病灶呈膨胀性肿块
B.病灶周围可见低信号环
C.可见液-液平面
D.表现为多发性囊腔
E.病灶中可见钙化
参考答案:B, C, D
Paul isn’t as ______ as Sandy. He often makes mistakes in his homework.
A.careless
B.more careful
C.more careless
D.careful
单位体积气体中所含的粉尘(),称为气体中的粉尘浓度。
A、数量
B、质量
C、占有量
D、容量