女性，35岁，颈前区肿块10年，近年来易出汗、心悸，渐感呼吸困难。体检：晨起心率104次/分，BP120/60mmHg，无突眼，甲状腺Ⅲ度肿大，结节状，心电图示：窦性心率不齐。（以下3题共用题干）

初步诊断最可能的是（ ）。

A．原发性甲亢

B．单纯性甲状腺肿

C．继发性甲亢

D．桥本甲状腺炎

E．亚急性甲状腺炎

Only when the final examination was coming ________ he had quite a lot to do. [ ]

A. he realized  

B. he had realized

C. did he realize  

D. had he realized