典型的后方回声增强不常见于哪项含液性结构
A.囊肿
B.新鲜血肿
C.囊状扩张的肝内胆管
D.扩张的肾盂和输尿管
E.胸膜腔积液
参考答案:B
The candidate was about to get in the car _ suddenly a man with a mask appeared and shot at him.
A.while
B.after
C.as
D.when
在一个周期内相继出现几个不同闪光次数的联闪光为()。
A.明暗光
B.联闪光
C.混合联闪光
D.长闪光