超声显示胰头肿大伴有扩张的胆管、胰管，提示胰头病变最可能为
A．急性胰腺炎
B．慢性胰腺炎
C．假性囊肿
D．良性肿瘤.
E． 癌
参考答案：E
把钢中横波折射角为50°的斜探头移至横波声速为2.17×103m/s的材料上，则折射角约为（）。
A、53°
B、35°
C、31°
D、47°
She felt disappointed when she found out they had gone swimming____ her.
A．but
B．except
C．except for
D．without
