Never ______ so excited because it is the first time that I ______ such a fantastic experience.

A．I have been; had

B．have I been; have had

C．have I been; had had

D．I have been; have

患者女，28岁，因“人工流产术后 * * 不规则出血2个月”来诊。查体：子宫增大如孕3个月大小，质软。尿妊娠试验（＋）。临床拟诊为绒毛膜癌。

对诊断绒毛膜癌最有帮助的特异性声像图表现是（）。

A.子宫增大，超过妊娠周数

B.子宫肌层内血流异常丰富紊乱，并探及动静脉瘘样频谱

C.子宫肌层回声不均匀

D.子宫肌层变薄

E.宫腔内充满大小不等无回声区，呈“蜂窝状”