The achievements of the greatest minds in science could never have been reached if it had not been for the patient and accurate work of hundreds of other people.

A．has it not been

B．if it had been

C．if hasn't been

D．had it not been

一4岁儿童反复发作性眩晕伴波动性听力下降，高分辨CT颞骨扫描，轴位CT上测量前庭水管直径为2．5mm，其可能诊断是（）。

A.先天性耳蜗畸形

B.Mondini内耳发育不全

C.米歇尔聋

D.沙伊贝聋

E.大前庭水管综合征